Introduzione

In questo documento vengono trattati i seguenti argomenti:

  • Note relative all'installazione

  • Aggiornamento dei contenuti

  • Aggiornamenti del driver

  • Aggiornamenti del kernel

  • Virtualization

  • Technology Preview

  • Problematiche risolte

  • Problematiche conosciute

Some updates on Red Hat Enterprise Linux 5.2 may not appear in this version of the Release Notes. An updated version may also be available at the following URL:

http://www.redhat.com/docs/manuals/enterprise/

Note relative all'installazione

This section includes information specific to Anaconda and the installation of Red Hat Enterprise Linux 5.2.

To upgrade an already-installed Red Hat Enterprise Linux 5, you can use Red Hat Network to update those packages that have changed. Alternatively, you can also use Anaconda to perform a fresh installation of Red Hat Enterprise Linux 5.2 or to upgrade an already-installed Red Hat Enterprise Linux 5.

Note that upgrading from beta releases to GA releases is not supported. Further, Red Hat does not support in-place upgrades between major versions of Red Hat Enterprise Linux. Although Anaconda provides an option that allows an upgrade from earlier major versions of Red Hat Enterprise Linux (such as Enterprise Linux 4 to Enterprise Linux 5), there is no guarantee that the upgrade will result in a fully functional configuration. In-place upgrades across major releases do not preserve all system settings, services, and custom configurations. For this reason, Red Hat strongly recommends that you perform a fresh installation rather than a system upgrade between major versions.

  • When installing from CD-ROM or DVD-ROM on a system with an iBFT-configured network device, Anaconda will not include any iBFT-configured storage devices unless networking is configured. To enable networking for the installation, use the command linux updates=http://[any] at the installation boot prompt. Note that [any] can be replaced with any URL.

    If your system requires a static IP configuration, use the command linux updates=http://[any] ip=[IP address] netmask=[netmask] dns=[dns].

  • If you are copying the contents of the Red Hat Enterprise Linux 5 CD-ROMs (in preparation for a network-based installation, for example) be sure to copy the CD-ROMs for the operating system only. Do not copy the Supplementary CD-ROM, or any of the layered product CD-ROMs, as this will overwrite files necessary for Anaconda's proper operation.

    The contents of the Supplementary CD-ROM and other layered product CD-ROMs must be installed after Red Hat Enterprise Linux 5.2 is installed.

  • When installing Red Hat Enterprise Linux 5.2 on a fully virtualized guest, do not use the kernel-xen kernel. Using this kernel on fully virtualized guests can cause your system to hang.

    If you are using an Installation Number when installing Red Hat Enterprise Linux 5.2 on a fully virtualized guest, be sure to deselect the Virtualization package group during the installation. The Virtualization package group option installs the kernel-xen kernel.

    Questo problema non interessa i guest paravirtualizzati. I suddetti guest utilizzano sempre il kernel kernel-xen.

  • If you are using the Virtualized kernel when upgrading from Red Hat Enterprise Linux 5 to 5.2, you must reboot after completing the upgrade. You should then boot the system using the updated Virtualized kernel.

    The hypervisors of Red Hat Enterprise Linux 5 and 5.2 are not ABI-compatible. If you do not boot the system after upgrading using the updated Virtualized kernel, the upgraded Virtualization RPMs will not match the running kernel.

  • When upgrading to Red Hat Enterprise Linux 5.1 or later from Red Hat Enterprise Linux 4.6, gcc4 may cause the upgrade to fail. As such, you should manually remove the gcc4 package before upgrading.

  • The firstboot language plugin has been removed, as this plugin does not properly and completely reconfigure the system when a new language is selected.

  • The use of Challenge Handshake Authentication Protocol (CHAP) during installation is not supported. As such, CHAP should only be enabled after installation.

    If your system boots through an iFBT device, configure CHAP in the iFBT BIOS/firmware setup screen. Your CHAP settings will then be used in the next boot.

    If your system boots through PXE iSCSI, configure CHAP through iscsiadm. After configuring, use mkinitrd to ensure that your CHAP settings are used in the next boot.

Aggiornamenti dei contenuti

Systemtap

Systemtap fornisce una infrastruttura (GPL) del software libero, in grado di facilitare la raccolta delle informazioni sul sistema Linux in esecuzione. Ciò assiste nel processo di diagnosi di un problema riguardante la prestazione o funzionalità. Con l'aiuto di systemtap, gli sviluppatori non avranno alcun bisogno di seguire la sequenza di ricompilazione, installazione e di riavvio altrimenti necessaria per ottenere i dati.

Systemtap is now fully supported. For more information about Systemtap, refer to http://sources.redhat.com/systemtap.

iSNS-utils

Internet storage name service for Linux (isns-utils) is now supported. This allows you to register iSCSI and iFCP storage devices on the network. isns-utils allows dynamic discovery of available storage targets through storage initiators.

isns-utils provides intelligent storage discovery and management services comparable to those found in fibre-channel networks. This allows an IP network to function in a similar capacity as a storage area network.

With its ability to emulate fibre-channel fabric services, isns-utils allows seamless integration of IP and fibre-channel networks. In addition, isns-utils also provides the utilities for managing both iSCSI and fibre-channel devices within the network.

For more information about the specifications of isns-utils in this release, refer to http://tools.ietf.org/html/rfc4171. For usage instructions, refer to /usr/share/docs/isns-utils-[version]/README and /usr/share/docs/isns-utils-[version]/README.redhat.setup.

rsyslog

rsyslog is an enhanced multi-threaded syslogd daemon that supports the following (among others):

  • MySQL

  • syslog/tcp

  • RFC 3195

  • permitted sender lists

  • filtering on any message part

  • more granular output format control

rsyslog is compatible with the stock sysklogd, and can be used as a replacement in most cases. Its advanced features make it suitable for enterprise-class, encrypted syslog relay chains; at the same time, its user-friendly interface is designed to make setup easy for the novice user.

For more information about rsyslog, refer to http://www.rsyslog.com/.

OpenSwan

OpenSwan is a free implementation of Internet Protocol Security (IPSEC) and IKE for Linux. IPSEC uses strong cryptography to provide authentication and encryption services. These services allow you to build secure tunnels through untrusted networks. Everything passing through the untrusted network is encrypted by the IPSEC gateway machine and decrypted by the gateway at the other end of the tunnel. The resulting tunnel is a virtual private network (VPN).

This release of OpenSwan also contains an IKE2 daemon that conforms to IETF RFCs. For more information about OpenSwan, refer to http://www.openswan.org/.

Evolution

The Evolution update for this release now features the following enhancements (among others):

  • Bogofilter compatibility for filtering junk mail.

  • An option to receive pop-up notifications for new mail.

  • Improved performance for downloading messages from a Microsoft Exchange™ server.

  • A setup assistant to guide you through the process of backing up and restoring data/settings.

Password Hashing Using SHA-256/SHA-512

Password hashing using the SHA-256 and SHA-512 hash functions is now supported.

To switch to SHA-256 or SHA-512 on an installed system, run authconfig --passalgo=sha256 --update or authconfig --passalgo=sha512 --update. To configure the hashing method through a GUI, use authconfig-gtk. Existing user accounts will not be affected until their passwords are changed.

For newly installed systems, using SHA-256 or SHA-512 can be configured only for kickstart installations. To do so, use the --passalgo=sha256 or --passalgo=sha512 options of the kickstart command auth; also, remove the --enablemd5 option if present.

If your installation does not use kickstart, use authconfig as described above, then change all passwords (including root) created after installation.

Appropriate options were also added to libuser, pam, and shadow-utils to support these password hashing algorithms. authconfig configures necessary options automatically, so it is usually not necessary to modify them manually:

  • New values of the crypt_style option and new options for both hash_rounds_min and hash_rounds_max are now supported in the [defaults] section of /etc/libuser.conf. For more information, refer to man libuser.conf.

  • New options sha256, sha512, and rounds are now supported by the pam_unix PAM module. For more information, refer to /usr/share/doc/pam-[pam version]/txts/README.pam_unix.

  • The following new options in /etc/login.defs are now supported by shadow-utils:

    • ENCRYPT_METHOD — Specifies the encryption methos to be used. Valid values are DES, MD5, SHA256, SHA512. If this option is defined, MD5_CRYPT_ENAB is ignored.

    • SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS — Specifies the number of hashing rounds to use if ENCRYPT_METHOD is set to SHA256 or SHA512. If neither option is set, a default value is chosen by glibc. If only one option is set, the encryption method specifies the number of rounds.

      If both options are used, they specify an inclusive interval from which the number of rounds is chosen randomly. The selected number of rounds is limited to the inclusive interval [1000, 999999999].

nfsroot

nfsroot is fully supported in this update. This allows users to run Red Hat Enterprise Linux 5.2 with its root file system (/) mounted via NFS.

nfsroot was originally introduced in Red Hat Enterprise Linux 5 as a subset of the Technology Preview feature Stateless Linux. The full implementation of Stateless Linux remains a Technology Preview.

Al momento nfsroot presenta le seguenti restrizioni:

  • Writable directories that hold system files (for example, /tmp, /var, and /etc) must be replicated for each client and mounted independently with no sharing between clients. To do so, perform the following steps:

    1. Configure the client's root file system to boot in read-only mode. To do so, replace READONLY with yes in /etc/sysconfig/readonly-root.

    2. Run cat /etc/rwtab to view a default list of directories and files mounted by each client in the format [type] [path].

      [type] can be either empty (an empty path), dirs (a directory tree that is copied, but is empty), or files (a file or directory tree copied intact).

    3. If any other files or directories need to writable but are not in /etc/rwtab, list them in the same format (i.e. [type] [path]) in a file under /etc/rwtab.d/.

  • SWAP non è supportato attraverso NFS.

  • SELinux non può essere abilitato sui client nfsroot. In generale Red Hat non consiglia di disabilitare SELinux. Per questo motivo gli utenti devono considerare gli effetti negativi che si possono avere sulla sicurezza, se si desidera eseguire tale azione.

OFED in comps.xml

The group OpenFabrics Enterprise Distribution is now included in comps.xml. This group contains components used for high-performance networking and clustering (for example, InfiniBand and Remote Direct Memory Access).

Further, the Workstation group has been removed from comps.xml in the Red Hat Enterprise Linux 5.2 Client version. This group only contained the openib package, which is now part of the OpenFabrics Enterprise Distribution group.

Frysk

The goal of the frysk project is to create an intelligent, distributed, always-on system monitoring and debugging tool that allows developers and system administrators to:

  • controllare thread e processi in esecuzione (incluso la creazione e distribuzione degli eventi)

  • controllare l'uso del locking delle primitive

  • esporre i deadlock

  • raccogliere dati

  • eseguire il debug di qualsiasi processo attraverso la sua selezione tramite elenco, o permettendo a frysk di aprire una finestra del codice sorgente (o altro), su di un processo che si comporta in modo anomalo o soggetto ad interruzioni inaspettate 'crash'.

This updated version of frysk includes the following new utilities:

  • fauxv

  • fdebuginfo

  • fdebugrpm

  • ferror

  • fexe

  • fmaps

In addition to this, ftrace can now perform signal and function symbol tracing. In previous releases, ftrace could only perform system call tracing.

frysk was introduced in Red Hat Enterprise Linux 5, and is still included in this release as a Technology Preview. For more information about frysk, refer to http://sources.redhat.com/frysk/.

Aggiornamenti del driver

General Driver/Platform Updates
  • The driver that allows hot docking/undocking of laptops is now updated to eliminate specific panic situations (for example, when a laptop fails to initialize correctly). This update also adds new sysfs entries, most notably:

    • /sys/devices/platform/dock.0/docked — read-only; indicates whether the laptop is docked on a docking station.

    • /sys/devices/platform/dock.0/undock — write-only; writing to this file initiates an "undock" request to the firmware.

    • /sys/devices/platform/dock.0/uid — displays the unique ID (UID) of the docking station.

  • Added the necessary PCI IDs to support the Intel E7221 Graphic Controller.

  • Added the necessary sub-device IDs to support the PCI-Express icom WAN adapter.

  • i2c-piix4 kernel module is now enabled to support the AMD SBX00 SMBus.

  • The following kernel configuration flags are now enabled to enhance kernel panic handling for Intelligent Platform Management Interface (IPMI):

    • CONFIG_IPMI_PANIC_EVENT — when a panic occurs, the IPMI message handler generates an IPMI event describing the panic to each interface registered with the message handler.

    • CONFIG_IPMI_PANIC_STRING — when a panic occurs, OEM events containing the panic string are generated.

    In addition to this, IPMI now supports the IBM Bladecenter QS21 and QS22.

  • The tlclk driver is now included to support the Intel MPCBL0050 systems.

  • All PCI-X configuration registers (up to 4096 bytes) are now accessible.

  • The maximum length of the kernel command line is now 2,048 bytes. To use this increased maximum length, upgrade the grub package.

  • Dynamic acceleration is now supported. This allows a core to run at a higher-than-normal frequency when all CPUs (as a whole) are operating below maximum power.

Graphics/Audio
  • High-Definition Multimedia Interface (HDMI) audio is now supported on AMD ATI integrated chipsets.

  • The Intel Xorg driver now provides enhanced support for i915 (and later) chips. This driver is also the default driver now for such chips.

    Basic runtime multi-head support is provided by the intel Xorg driver. Selecting a resolution with the System = > Preferences = > Screen Resolution tool (gnome-display-properties) will set that resolution on all connected outputs.

  • The Sony/Philips Digital Interconnect Format (S/PDIF) port on the Dell D/Dock Expansion Station is now supported by the Dell M4300 and M6300 Precision Workstations. This allows digital audio output through the S/PDIF port on the Dell D/Dock Expansion Station when either the M4300 or M6300 is docked.

Rete
  • bnx2x: driver added to provide support for bcm5710 hardware.

  • tg3: updated to version 3.86. This update enables support for BroadCom 5761 and 5784 devices.

Storage
  • lpfc: updated to version 8.2.0.22. This update applies several devloss fixes, and enables support for the following:

    • 1, 2, 4, and 8GB auto-rate negotiation.

    • FC-SP DH-CHAP Authentication.

    • The latest HBAnyware configuration utility, which is also part of the driver master kit. This enables GUI-based driver configuration (including fibre channel and TCP/IP remote storage area network management), diagnostics (loopback and diagnostics dump) and FC-SP/Authentication Diffie-Hellman CHAP (DH-CHAP).

    • LPe1250, LPe1252, LPe12000 and LPe12002 (2, 4, and 8Gb capable HBAs).

    • NPIV virtual ports.

  • megaraid_sas: updated to version 3.15. This applies several upstream changes, most notably:

    • Added the following module parameters:

      • fast_load: enables the driver to load faster by skipping physical device check.

      • cmd_per_lun: sets the maximum number of commands per logical unit.

      • max_sectors: sets the maximum number of sectors per I/O command.

      • poll_mode_io: enables support for polling (i.e. reduced interrupt operations). When poll_mode_io is set, commands will also be completed from the I/O path.

    • Added support for hibernation.

    • SYNCHRONIZE_CACHE is now blocked by the driver.

  • aacraid: updated to version 1.1.5-2453. This applies several upstream changes, most notably:

    • Fixed a bug that caused aacraid to use an incorrect dma mapping mask during firmware assert recovery.

    • Added the capability to issue a hardware reset to the adapter via sysfs. In line with this, the following check features were also added:

      • check_interval — for checking adapter health

      • update_interval — for revising time intervals used by adapter

      • check_reset — for blocking adapter checks/resets

    • Added a SYNCHRONIZE_CACHE call to implement a more effective cache flushing schedule. This helps reduce application stalls resulting from multiple applications issuing I/O commands to the storage device.

    • Replaced all if/else packet formations with platform function calls.

    • VPD inquiry pages are now supported. This ensures that when an array is created, the metadata stored on the physical device is issued a unique serial number. This serial number remains constant throughout array morphing or migration to other controllers.

  • qla2xxx: updated to version 8.02.00-k5. This update to qla2xxx adds support for the following:

    • EHAFT, a QLogic host bus adapter mechanism that provides activity information about fibre channel devices.

    • N_Port ID Virtualization (NPIV), which allows multiple N_Port IDs to share a single physical N_Port. This allows you to tie virtualized guests to fibre-channel identifiers, allowing those guests to migrate between hosts while retaining their access in the storage area network.

    • 8GB fibre-channel devices.

    • PCI EE error handling.

    This update also applies several improvements provided from upstream.

  • mpt fusion: updated to version 3.04.05. This update provides several changes, most notably:

    • On-the-fly logging (via the sysfs shost attribute) is now supported.

    • Added new sysfs shost attributes that provide the following:

      • board_name

      • board_assembly

      • board_tracer

      • unique_id

      • version_bios

      • version_fw

      • version_product

      • version_mpi

      • version_nvdata_default

      • version_nvdata_persistent

      • debug_level

      • io_delay

      • device_delay

    • task_abort calls are no longer sent to hidden RAID components and volumes.

    • Changes related to fibre channel:

      • Brocade, a rebranded FC949E fibre channel controller, is now supported.

      • Link speeds are now displayed when the driver is loaded and whenever the link speed changes.

      • High-priority request queueing is now used instead of the handshake/doorbell system when sending management requests for SAS or fibre channel.

    • Changes related to parallel SCSI:

      • ATTO UL4D, a rebranded SPI 1030 controller, is now supported.

      • mptspi_target_destroy is now declared as static.

Aggiornamenti relativi al Kernel

This release applies following kernel bug fixes:

  • Executing binaries with more than 2GB of debug information no longer fails.

  • When shutting down a database, all allocated hugepages are now released upon shutdown.

  • invalidate_mapping_pages() calls no longer cause soft lockups.

  • A bug that delayed oomkill from launching in a timely fashion (on systems with large memory) is now fixed.

  • A bug that caused soft lockup warnings when allocating memory on a system with large memory is now fixed.

  • 32-bit NFS clients can now correctly process 64-bit inode numbers.

  • The kernel now asserts Data Terminal Ready (DTR) signals before printing to serial ports during boot time. DTR assertion is required by some devices. Kernel boot messages are now printed to serial consoles on such devices.

  • The kernel parameter ide0=noprobe no longer causes a kernel panic.

This kernel update also features the following enhancements:

  • Added a new kernel parameter: /proc/sys/vm/flush_mmap_pages. This parameter specifies whether or not memory-mapped file pages should be flushed to disk by kupdate while the memory map is active. Valid values for this parameter are 1 (enable memory mapping by kupdate) and 0 (disable memory mapping by kupdate). The default value for this parameter is 1.

    To configure this parameter, use echo [1 or 0] /proc/sys/vm/flush_mmap_pages. Setting this parameter to 0 does the following:

    • kupdate will not flush dirty memory-mapped file pages as long as the memory map is active.

    • All dirty file pages will be asynchronously flushed to disk only as soon as the memory map is deactivated.

    If you set /proc/sys/vm/flush_mmap_pages to 0, it is advisable that you use another application to manually sync memory-mapped pages to disk.

  • Added a new kernel parameter: /proc/sys/kernel/sched_interactivity. This parameter allows you to tune the CPU scheduler's interactivity estimator. The interactivity estimator allows interactive processes to acquire more CPU time without causing CPU starvation in other processes.

    To configure this parameter, use echo [interactivity_level] > /proc/sys/kernel/sched_interactivity, where [interactivity_level] can be any of the following:

    • 2 — interactivity estimator is fully activated.

    • 1 — provides a weaker affinity to interactive processes than 2, but avoids CPU starvation under certain scheduling patterns.

    • 0 — any bias or affinity towards interactive processes is disabled.

  • kprobe now supports kretprobe_blacklist[].

  • Core dump masking is now supported. This allows a core dump process to skip the shared memory segments of a process when creating a core dump file. This feature also allows you to select whether or not to dump anonymous shared memory for each process.

    When a process is dumped, all anonymous memory is written to a core file as long as the size of the core file isn't limited. In some cases, you may want to prevent some memory segments (such as huge shared memory) from being dumped. Conversely, you may also want to save file-backed memory segments into a core file, in addition to individual files.

    For these purposes, you can use /proc/[pid]/coredump_filter to specify which memory segments of the [pid] process is dumped. coredump_filter is a bitmask of memory types. If a bitmask is set, memory segments of the corresponding memory type are dumped.

    The following memory types are supported:

    • 0x0 — anonymous private memory

    • 0x1 — anonymous shared memory

    • 0x2 — file-backed private memory

    • 0x3 — file-backed shared memory

    To set a bitmask for [pid], simply echo the corresponding bitmask to /proc/[pid]/coredump_filter. For example, to prevent a dump of all shared memory segments attached to process 1111, use:

    echo 0x1 > /proc/1111/coredump_filter

    The default value of coredump_filter is 0x3, which specifies that all anonymous memory segments are dumped. Also, note that regardless of the bitmask status, MMIO pages (such as frame buffers) are never dumped and vDSO pages are always dumped

    When a new process is created, the process inherits the bitmask status from its parent. As such, it is recommended that you set up coredump_filter before the program runs. To do so, echo the desired bitmask to /proc/self/coredump_filter before running the program.

  • audit can now trace and display per-session user activity.

  • REV UDF file sizes larger than 1GB are now supported.

  • Lock contention tracing and lockdep are now supported. These features provide in-depth information about spinlocks held in the kernel, which in turn help developers in driver debugging.

In addition to these, this release also features the following kernel updates:

  • The enumeration order of PCI devices has changed on several platforms to have NICs appear in the order they are labeled on the chassis and how the BIOS numbers them. The affected platforms are as follows:

    • Dell PowerEdge R900

    • HP ProLiant DL385 G2

    • HP ProLiant DL585 G2

    • HP Proliant DL580 G5

    Note that this change affects new installations only. If you prefer the old enumeration order, use the kernel parameter pci=nobfsort.

  • You can now determine the resource limit (rlimit) of a process. To do so, run cat /proc/[pid]/limits.

  • The maximum soft lockup timeout is now increased from 60 seconds to 300 seconds for systems that have a large number of CPUs. A soft lockup occurs when a CPU reports a memory starvation while it is unable to access a memory node accessed by other CPUs.

    In this release, you can also adjust the trigger limit for soft lockup warnings. To do so, use the following command (as root):

    echo [time] > /proc/sys/kernel/softlockup_thresh

    Replace [time] with the desired number of seconds before a soft lockup warning should be triggered. By default, this value is set to 10 (seconds).

  • show_mem() output now includes the total number of pagecache pages.

  • MSI-X is no longer enabled by default. To enable MSI-X, use the kernel module parameter ql2xenablemsix.

Virtualization

This section contains information about updates made to Red Hat Enterprise Linux suite of Virtualization tools.

Enhancements/Updates
  • When entering the second stage of a Windows™ Server 2003 installation, you no longer need to manually edit /etc/xen/[name of guest machine] to continue. The current user interface now allows you to change media on CD-ROMs attached to the guest.

  • The Virtual Machine Manager (virt-manager) included in this release now allows users to specify kernel boot parameters to the paravirtualized guest installer.

  • A wrong address translation (which can lead to a crashed guest) no longer occurs if a guest is running a PAE kernel with more than 3,840MB of RAM. As such, you no longer need to use the 64-bit kernel if you intend to run guests with more than 4GB of physical RAM under Rapid Virtualization Indexing (RVI).

  • During the lifetime of dom0, you can now create guests (i.e. xm create) more than 32,750 times.

  • When using virt-manager to add disks to an existing guest, duplicate entries are no longer created in the guest's /etc/xen/[domain name] configuration file.

Known Issues
  • Migrating paravirtualized guests through xm migrate [domain] [dom0 IP address] does not work.

  • Repeated live migration of paravirtualized guests between two hosts may cause one host to panic. If a host is rebooted after migrating a guest out of the system and before migrating the same guest back, the panic will not occur.

  • L'esecuzione di 16 o più nuclei utilizzando i processori AMD Rev F, potrebbe risultare nel resetaggio del sistema durante l'esecuzione delle installazioni del guest completamente virtualizzato.

  • When installing Red Hat Enterprise Linux 5 on a fully virtualized SMP guest, the installation may freeze. This can occur when the host (dom0) is running Red Hat Enterprise Linux 5.2.

    Per evitare questo tipo di comportamento impostate il guest per l'utilizzo di un processore singolo utilizzando il processo d'installazione. Per fare ciò utilizzate l'opzione --vcpus=1 in virt-install. Una volta completato il processo d'installazione potrete impostare il guest su SMP, modificando vcpus in virt-manager.

Technology Preview

Technology Preview features are currently not supported under Red Hat Enterprise Linux subscription services, may not be functionally complete, and are generally not suitable for production use. However, these features are included as a customer convenience and to provide the feature with wider exposure.

Gli utenti possono utilizzare queste caratteristiche in ambienti non di produzione, e fornire suggerimenti sulla loro funzionalità prima che le stesse caratteristiche di Technology preview possano essere supportate. Inoltre verranno forniti gli Errata per problematiche relative alla high-severity security.

Durante il ciclo di sviluppo di una Technology Preview, componenti aggiuntivi possono essere resi disponibili al pubblico solo a scopo di prova. È intenzione di Red Hat supportare pienamente le suddette caratteristiche di Technology Preview all'interno di release future.

ALUA Mode on EMC Clariion

Explicit active-passive failover (ALUA) mode using dm-multipath on EMC Clariion storage is now available. This mode is provided as per T10 specifications, but is provided in this release only as a technology preview.

For more information about T10, refer to http://www.t10.org.

radeon_tp

The radeon_tp driver is now included in this release as a Technology Preview. This driver enables the ATI R500/R600 chipsets.

This driver also features the following capabilities:

  • Modesetting on R500/R600 chipsets

  • 2D acceleration on R500 chipsets

  • Shadow framebuffer acceleration on R600 chipsets

FreeIPMI

FreeIPMI is now included in this update as a Technology Preview. FreeIPMI is a collection of Intelligent Platform Management IPMI system software. It provides in-band and out-of-band software, along with a development library conforming to the Intelligent Platform Management Interface (IPMI v1.5 and v2.0) standards.

For more information about FreeIPMI, refer to http://www.gnu.org/software/freeipmi/

TrouSerS and tpm-tools

TrouSerS and tpm-tools are included in this release to enable use of Trusted Platform Module (TPM) hardware.TPM hardware features include (among others):

  • Creation, storage, and use of RSA keys securely (without being exposed in memory)

  • Verification of a platform's software state using cryptographic hashes

TrouSerS is an implementation of the Trusted Computing Group's Software Stack (TSS) specification. You can use TrouSerS to write applications that make use of TPM hardware. tpm-tools is a suite of tools used to manage and utilize TPM hardware.

For more information about TrouSerS, refer to http://trousers.sourceforge.net/.

eCryptfs

eCryptfs is a stacked cryptographic file system for Linux. It mounts on individual directories in existing mounted lower file systems such as EXT3; there is no need to change existing partitions or file systems in order to start using eCryptfs.

eCryptfs stores cryptographic metadata in the header of each file written to the lower file system. This enables you to copy encrypted files between hosts or directly onto backup media. Files encrypted and copied in this manner can be decrypted with the proper key.

This release's version of eCryptfs provides several key management options, including protection based on passphrases and public keys. Below is a list of other fully functional features:

  • Interactive and non-interactive mounting.

  • Compatibility with SELinux.

  • Cryptographic metadata storage in both xattrs and file headers.

At present, the following issues still exist with eCryptfs:

  • direct_IO is not implemented.

  • Complex I/O patterns within the mmap implementation in eCryptfs may cause data corruption in some cases.

  • eCryptfs cannot be used for root file systems.

For more information about eCryptfs, refer to http://ecryptfs.sf.net. You can also refer to http://ecryptfs.sourceforge.net/README and http://ecryptfs.sourceforge.net/ecryptfs-faq.html for basic setup information.

GFS2

GFS2 rappresenta un miglioramento di GFS. Questo aggiornamento implementa miglioramenti rilevanti, che necessitano di una modifica al formato del file system sul disco. I file system GFS possono essere convertiti in GFS2 utilizzando l'utilità gfs2_convert, la quale aggiorna i metadata di un file system GFS.

While much improved since its introduction in Red Hat Enterprise Linux 5, GFS2 remains a Technology Preview. Benchmark tests indicate faster performance on the following:

  • utilizzo esteso in una directory singola con scansione più veloce della directory (Postmark benchmark)

  • operazioni I/O sincrone (le prove di fstest indicano una migliore prestazione per le applicazioni di messaggistica come TIBCO)

  • letture della cache, poichè non sono più presenti gli overhead del blocco

  • I/O diretto per file preassegnati

  • Ricerche di gestione del file NFS

  • df, poichè le informazioni per l'assegnazione sono ora conservate nella cache

In aggiunta GFS2 presenta anche le seguenti modifiche:

  • I registri sono ora file semplici (nascosti) invece di metadata. Essi possono essere aggiunti dinamicamente mentre server aggiuntivi eseguono il montaggio di un file system.

  • i quota sono ora abilitati e disabilitati dal mount point quota=<on|off|account>

  • Non è più necessario quiesce su di un cluster per rispondere ai registri per il ripristino da un errore

  • sono ora supportati i timestamp in nanosecondi

  • simile a ext3, GFS2 ora supporta la modalità data=ordered

  • le impostazioni di lsattr() e chattr() sono ora supportate tramite ioctl() standard

  • sono ora supportate le dimensioni del file system superiori a 16TB

  • GFS2 è un file system standard, e può essere usato in configurazioni non clusterizzate

Stateless Linux

Stateless Linux rappresenta una nuova concezione su come eseguire e gestire un sistema, ideato per semplificare il provisioning e la gestione di un numero esteso di sistemi tramite una loro semplice sostituzione. È possibile eseguire tale procedimento creando alcune immagini del sistema pronte all'uso, le quali verranno replicate e gestite attraverso un numero esteso di sistemi stateless, in grado di eseguire il sistema operativo in modalità di sola lettura (per maggiori informazioni consultate /etc/sysconfig/readonly-root).

Nel suo stato attuale di sviluppo le caratteristiche Stateless rappresentano i sottoinsiemi degli obiettivi desiderati. Per questo, esse sono state denominate Technology Preview.

It is highly recommended that those interested in testing stateless code read the HOWTO at http://fedoraproject.org/wiki/StatelessLinux/HOWTO and join [email protected].

The enabling infrastructure pieces for Stateless Linux were originally introduced in Red Hat Enterprise Linux 5.

AIGLX

AIGLX è una Technology Preview del server X supportato. La sua funzione è quella di abilitare gli effetti GL-accelerati su di un desktop standard. Il progetto consiste in:

  • A lightly modified X server.

  • An updated Mesa package that adds new protocol support.

Installando questi componenti è possibile ottenere effetti GL-accelerati sul vostro desktop con poche modifiche, abilitandoli e disabilitandoli a vostro piacimento senza sostituire il vostro server X. AIGLX abilita altresì applicazioni GLX remote, in modo da trarre vantaggio dall'accelerazione GLX hardware.

mac80211 802.11a/b/g WiFi protocol stack (mac80211)

The mac80211 stack (formerly known as the devicescape/d80211 stack) enables the iwlwifi 4965GN wireless driver for Intel Wifi Link 4965 hardware. This stack allows certain wireless devices to connect to any Wi-Fi network.

Although the stack is already accepted upstream, the stability of this stack is yet to be verified through testing. As such, this stack is included in this release as a Technology Preview.

FS-Cache

FS-Cache is a local caching facility for remote file systems that allows users to cache NFS data on a locally mounted disk. To set up the FS-Cache facility, install the cachefilesd RPM and refer to the instructions in /usr/share/doc/cachefilesd-[version]/README.

Replace [version] with the corresponding version of the cachefilesd package installed.

Target iSCSI

Il framework del target di Linux (tgt) permette di servire il block-level SCSI storage, ad altri sistemi con un inizializzatore SCSI. Questa funzione è stata inizialmente implementata come target iSCSI di Linux, per servire lo storage, attraverso una rete, a qualsiasi inizializzatore iSCSI.

Per impostare il target iSCSI installate l'RPM scsi-target-utils e consultate le istruzioni presenti in:

  • /usr/share/doc/scsi-target-utils-[version]/README

  • /usr/share/doc/scsi-target-utils-[version]/README.iscsi

Replace [version] with the corresponding version of the package installed.

Per maggiori informazioni consultate man tgtadm.

FireWire

The firewire-sbp2 module is still included in this update as a Technology Preview. This module enables connectivity with FireWire storage devices and scanners.

Al momento FireWire non supporta:

  • IPv4

  • controllori host pcilynx

  • dispositivi di storage multi-LUN

  • accesso non-esclusivo ai dispositivi di storage

In addition, the following issues still exist in FireWire:

  • una perdita di memoria nel driver SBP2 potrebbe causare la mancanza di reattività della macchina.

  • un codice presente in questa versione non funziona correttamente in macchine big-endian. In questo caso potrebbe verificarsi un comportamento inaspettato in PowerPC.

Problematiche risolte

  • Netapp devices can now complete failback (after a previously-failed path is restored) within a reasonable time with the default dm-multipath configuration.

  • system-config-kickstart now supports package selection through the Red Hat Network plugin.

  • kudzu can now properly parse ifcfg-* files that contain quotes around the HWADDR or SUBCHANNELS parameters. In addition, kudzu no longer modifies network configurations on device change if the device's HWADDR is not specified.

  • Running netstat with the -A inet or -A inet6 option (on a system where sctp was not added to the kernel) no longer terminates abnormally. Note, however, that netstat will display the following warning message when invoked with the -s option:

    netstat: no support for `AF INET (sctp)' on this system.
    
  • The nohide export option is no longer required on referral exports (i.e. exports that specify a referral server). For more information on bound mounts, refer to man 5 exports.

  • The priority callouts of dm-multipath are now statically compiled. This fixes a problem that occurs when running dm-multipath on devices containing the root file system, which caused such devices to freeze during fibre-channel path faults.

  • parted can now understand and correctly print out Xen Virtual Device (XVD) partition labels. This enables paravirtualized guests to now use the parted utility. As such, you no longer need to use parted within dom0 to configure disk partitions on paravirtualized guests.

  • When upgrading to Red Hat Enterprise Linux 5.2 via Red Hat Network, you no longer need to manually import the redhat-beta key prior to upgrading.

  • It is no longer necessary to use the kernel parameter pci=nommconf for systems that use the AMD 8132 or HT 1000 chipsets.

    Note that the system will still restrict such bridges to using the PortIO CF8/CFC mechanism. However, bridges (including those on the same platform) that respond correctly to MMCONFIG cycles will use MMCONFIG, provided that the platform's BIOS correctly supports MMCONFIG.

  • Previous versions of Red Hat Enterprise Linux 5 on HP BL860c blade systems could hang during the IP information request stage of installation. When this occurred, you were required to reboot and perform the installation with Ethernet autonegotiation disabled.

    This issue is now fixed in this update.

  • Gemalto 64K smart cards now use readers compliant with Chip/Smart Card Interface Devices (CCID). Previously, this smart card used the built-in e-gate reader, which essentially meant that the card and reader were being inserted at the same time. As a result, coolkey did not consistently recognize Gemalto 64K smart cards.

    In this update, coolkey now works correctly with Gemalto 64k smart cards.

Problematiche conosciute

  • A bug in the updated /etc/udev/rules.d/50-udev.rules file prevents the creation of persistent names for tape devices with numbers higher than 9 in their names. For example, a persistent name will not be created for a tape device with a name of nst12.

    To work around this, add an asterisk (*) after each occurrence of the string nst[0-9] in /etc/udev/rules.d/50-udev.rules.

  • Nested paging can only translate 32-bit guest virtual addresses. This is because of a hardware feature that exists only in 32-bit physical address extensions (PAE).

    Also, note that on an AMD NPT system used as a PAE host, guests cannot have more than 4GB of memory.

  • The smartctl tool cannot properly read SMART parameters from SATA devices.

  • When using dm-multipath, if features "1 queue_if_no_path" is specified in /etc/multipath.conf then any process that issues I/O will hang until one or more paths are restored.

    To avoid this, set no_path_retry [N] in /etc/multipath.conf (where [N] is the number of times the system should retry a path). When you do, remove the features "1 queue_if_no_path" option from /etc/multipath.conf as well.

  • Enabling multiple installed versions of the same kernel module is not supported. In addition to this, a bug in the way kernel module versions are parsed can sometimes result in enabling an older version of the same kernel module.

    It is recommended that when you install a newer version of an installed kernel module, you should delete the older one first.

  • Executing kdump on an IBM Bladecenter QS21 or QS22 configured with NFS root will fail. To avoid this, specify an NFS dump target in /etc/kdump.conf.

  • IBM T60 laptops will power off completely when suspended and plugged into a docking station. To avoid this, boot the system with the argument acpi_sleep=s3_bios.

  • La Scheda di espansione iSCSI di QLogic per IBM Bladecenter fornisce le funzioni iSCSI ed ethernet. Alcune parti presenti sulla scheda sono condivise da entrambe le funzioni. Tuttavia i driver correnti qla3xxx e qla4xxx supportano in modo individuale le funzioni ethernet e iSCSI. I suddetti driver non supportano l'utilizzo simultaneo delle funzioni ethernet e iSCSI.

    Because of this limitation, successive resets (via consecutive ifdown/ifup commands) may hang the device. To avoid this, allow a 10-second interval after an ifup before issuing an ifdown. Also, allow the same 10-second interval after an ifdown before issuing an ifup. This interval allows ample time to stabilize and re-initialize all functions when an ifup is issued.

  • I laptop con scheda wireless Cisco Aironet MPI-350, possono entrare in una fase di sospensione nel tentativo di ottenere un indirizzo DHCP durante qualsiasi installazione basata sulla rete, utilizzando una porta ethernet wired.

    Per risolvere questo problema utilizzate per la vostra installazione il media locale. Alternativamente disabilitate la scheda wireless nel BIOS del laptop prima di eseguire l'installazione (è possibile riabilitare la scheda wireless dopo aver completato l'installazione).

  • Boot-time logging to /var/log/boot.log is not available in Red Hat Enterprise Linux 5.2.

  • Il sistema potrebbe non eseguire correttamente il riavvio nel kernel kexec/kdump, se X risulta essere in esecuzione ed utilizza un driver diverso da vesa. Questo problema esiste solo con i chpset grafici ATI Rage XL.

    Se X è in esecuzione su di un sistema equipaggiato con ATI Rage XL, assicuratevi che esso stia utilizzando il driver vesa in modo da poter eseguire correttamente un processo di riavvio in un kernel kexec/kdump.

  • When using Red Hat Enterprise Linux 5.2 on a machine with an nVidia CK804 chipset installed, the following kernel messages may appear:

    kernel: assign_interrupt_mode Found MSI capability
    kernel: pcie_portdrv_probe->Dev[005d:10de] has invalid IRQ. Check vendor BIOS
    

    I suddetti messaggi indicano che determinate porte PCI-E non richiedono IRQ. Altresì essi non interessano in alcun modo, la normale funzionalità della macchina.

  • I dispositivi di storage estraibili (come ad esempio CD e DVD), non vengono montati automaticamente se siete registrati come utenti root. Per questo motivo sarà necessario montarli manualmente attraverso il file manager grafico.

    Alternativamente è possibile eseguire il seguente comando per montare un dispositivo su /media:

    mount /dev/[device name] /media
    
  • The IBM System z does not provide a traditional Unix-style physical console. As such, Red Hat Enterprise Linux 5.2 for the IBM System z does not support the firstboot functionality during initial program load.

    To properly initialize setup for Red Hat Enterprise Linux 5.2 on the IBM System z, run the following commands after installation:

    • /usr/bin/setup — fornito dal pacchetto setuptool.

    • /usr/bin/rhn_register — fornito dal pacchetto rhn-setup.

  • When a LUN is deleted on a configured storage system, the change is not reflected on the host. In such cases, lvm commands will hang indefinitely when dm-multipath is used, as the LUN has now become stale.

    Per risolvere questo problema cancellate tutti i dispositivi e le entry del link mpath in /etc/lvm/.cache, specifiche al LUN in questione.

    Per sapere quali sono queste entry eseguite il seguente comando :

    ls -l /dev/mpath | grep [stale LUN]

    For example, if [stale LUN] is 3600d0230003414f30000203a7bc41a00, the following results may appear:

    lrwxrwxrwx 1 root root 7 Aug  2 10:33 /3600d0230003414f30000203a7bc41a00 -> ../dm-4
    lrwxrwxrwx 1 root root 7 Aug  2 10:33 /3600d0230003414f30000203a7bc41a00p1 -> ../dm-5
    

    Ciò significa che 3600d0230003414f30000203a7bc41a00 viene mappato su due link mpath: dm-4 e dm-5.

    Per questo motivo le seguenti righe dovrebbero essere cancellate da /etc/lvm/.cache:

    /dev/dm-4 
    /dev/dm-5 
    /dev/mapper/3600d0230003414f30000203a7bc41a00
    /dev/mapper/3600d0230003414f30000203a7bc41a00p1
    /dev/mpath/3600d0230003414f30000203a7bc41a00
    /dev/mpath/3600d0230003414f30000203a7bc41a00p1
    
  • Running the multipath command with the -ll option can cause the command to hang if one of the paths is on a blocking device. Note that the driver does not fail a request after some time if the device does not respond.

    This is caused by the cleanup code, which waits until the path checker request either completes or fails. To display the current multipath state without hanging the command, use multipath -l instead.

  • Il sistema potrebbe non eseguire correttamente il riavvio nel kernel kexec/kdump, se X risulta essere in esecuzione ed utilizza un driver diverso da vesa. Questo problema esiste solo con i chpset grafici ATI Rage XL.

    Se X è in esecuzione su di un sistema equipaggiato con ATI Rage XL, assicuratevi che esso stia utilizzando il driver vesa in modo da poter eseguire correttamente un processo di riavvio in un kernel kexec/kdump.

  • Quando eseguite il kernel (non-Virtualizzato) bare-metal, il server X potrebbe non essere in grado di ripristinare le informazioni EDID dal monitor. Se si verifica questo comportamento, i driver grafici non saranno in grado di visualizzare le risoluzioni maggiori di 800x600.

    Per risolvere questo problema aggiungete la seguente riga alla sezione ServerLayout di /etc/X11/xorg.conf:

    Opzione "Int10Backend" "x86emu"
    
  • Upgrading pm-utils from a Red Hat Enterprise Linux 5.2 Beta version of pm-utils will fail, resulting in the following error:

    error: unpacking of archive failed on file /etc/pm/sleep.d: cpio: rename
                            

    To prevent this from occurring, delete the /etc/pm/sleep.d/ directory prior to upgrading. If /etc/pm/sleep.d contains any files, move those files to /etc/pm/hooks/.

  • Prove hardware per Mellanox MT25204 hanno rivelato la presenza di un errore interno sotto carichi di lavoro molto elevati. Quando il driver di ib_mthca riporta un errore catastrofico per questo hardware, esso si riferisce ad un completamento insufficiente della coda, relativo al numero di richieste pendenti generate dall'applicazione dell'utente.

    Although the driver will reset the hardware and recover from such an event, all existing connections at the time of the error will be lost. This generally results in a segmentation fault in the user application. Further, if opensm is running at the time the error occurs, then you need to manually restart it in order to resume proper operation.

  • When upgrading from Red Hat Enterprise Linux 4.6 to Red Hat Enterprise Linux 5.1 (or later), a warning error will appear stating that the kernel module mptscsi was not found. To prevent this, edit /etc/modprobe.conf by changing mptscsi to mptscsih before upgrading.

( x86 )



[1] Questo materiale può essere distribuito solo sotto i termini e le condizioni presenti nella Open Publication License, v1.0, disponibile su http://www.opencontent.org/openpub/.