CentOS-2 Enterprise Linux 2.1AS Release Notes --------------------------------------------- DISTRIBUTION GENERAL NOTES -------------------------- - CentOS-2 does not have any trademark restrictions. - This version already contains all the updates that were available at the time it was created. There may well be new updates available now. - After installation you MUST install all the required patches. The default firewall should prevent immediate problems but new security fixes may already be available. - Several configuration tools are included that you can use to configure: - networking (redhat-config-network) - time/date (redhat-config-date) - system control (redhat-config-services) - users/groups (redhat-config-users) - The IBM Java Runtime Environment (JRE) version 1.3.1 is NOT included. - GNOME 1.4 is included with this release and offers the Nautilus graphical shell and file manager. The Preferences folder is the GNOME control center. - Firewall Configuration -- For added security, you can configure a firewall as part of your system installation. You can choose from two levels of security, as well as choosing which common system services should be allowed or disallowed by default. Please note that both medium and high firewall settings will cause RPC-based services (such as NIS or NFS) to be blocked, and thus fail. - XFree86 4.1.0 is included with this release and provides improved hardware support. 3D hardware acceleration for the ATI Radeon is included. Most video drivers support the RENDER extension, providing anti-aliased font support to a wider range of hardware. The XIE and Pex (Phigs) X extensions are officially deprecated by the XFree86 team and will be removed from a future release of CentOS. - Sendmail, by default, does not accept network connections from any host other than the local computer. If you want to configure sendmail as a server for other clients, please edit /etc/mail/sendmail.mc and change DAEMON_OPTIONS to also listen on network devices, or comment out this option all together. You will need to regenerate /etc/sendmail.cf by running the following command as root: m4 /etc/mail/sendmail.mc > /etc/sendmail.cf NOTE: You must have the sendmail-cf package installed for this to work. - XFree86 3.3.6 is deprecated and will be removed from a future release of CentOS. It is currently included for compatibility. - The initscripts use /sbin/ip (from the iproute packages) for most operations. /sbin/ip requires the netlink and netlink routing features of the kernel to function properly; it is impossible to make use of the kernel's full routing functionality without these features. If you are building your own kernel, make sure that CONFIG_NETLINK and CONFIG_RTNETLINK are enabled. - Binutils and gcc support merging string constant duplicates across whole binaries or shared libraries (previously duplicates have been merged within a single compilation unit only). - The VNC package supports a new encoding type for low-bandwidth connections. - CentOS-2 includes the first release of the GNOME XSLT processor (xsltproc) using version 2 of the associated XML library. - ODBC-support is available for php, postgresql 7.1.2 is included, and python and perl interfaces are provided with this release. - The following packages/features are deprecated, and may be removed in a future CentOS-2 release: - Netscape 4.x - Qt 1.x - KDE v1 compatibility libraries/build environment - Red Hat Linux 6.x build environment - Enlightenment window manager - linuxconf - ncpfs - mars_nwe - XFree86 3.3.x - kaffe - Do not remove the /initrd directory for any reason. Removing this directory will cause your system to fail to boot with a kernel panic error message. ANACONDA/INSTALLER NOTES ------------------------ Bootloader ---------- - CentOS uses GRUB as the default boot loader. - GRUB supports a password that controls access to the GRUB shell; because of GRUB's ability to run arbitrary commands, this can be an important aspect in maintaining system security. Please carefully consider the implications of this before deciding whether or not to set a GRUB password. This password is encrypted using MD5; see the grub-md5-crypt man page for more information. - If you are using the GRUB boot loader, please note that you do not have to re-run GRUB after upgrading your kernel. This is different from the LILO boot loader, which required re-running LILO after each change. Simply modifying GRUB's configuration file (/boot/grub/grub.conf) to point to your new kernel will allow GRUB to boot it. - If you decide to switch to using the GRUB boot loader after installation, or you need to reinstall GRUB, you may do so using the /sbin/grub-install command. The command syntax must include the device specification showing where the boot loader should be installed. Example: /sbin/grub-install /dev/hda - To boot into single-user mode from GRUB, do the following from the GRUB menu screen: 1. Select the desired kernel. 2. Press the 'e' key to edit that entry. 3. Use the arrow keys to navigate to the kernel line (for example: kernel /vmlinuz-2.4.7-1 ro root=/dev/hda2) 4. Press the 'e' key to edit the line. 5. Add the argument 'single' to the end of the line and press return. 6. Press the 'b' key to boot. Partitioning ------------ - The Disk Druid user interface has been designed to take advantage of a graphical environment. - Disk Druid can create primary partitions by specifying a cylinder range. - Disk Druid supports the ability to specify that a new partition must be created as a primary partition. - Text mode installations have support for creating RAID devices. - Specifying spare drives for RAID devices is supported. - Autopartitioning allows you to specify which drives to use, and which to avoid touching at all. - Disk Druid provides an option to view and edit the results of autopartitioning (for graphical installations only -- under text mode you will always see the results). - The ext3 journaling file system is available. - Pre-existing file systems may be selected for reformatting during the installation. Pre-existing ext2 file systems may be migrated to ext3 during installation. This process does not affect the data on the file system. - Many additional sanity checks are made against user-created mount points; this should avoid most common problems (such as a '/' mount point of only 5 MB). - GNU Parted is used as the partitioning backend (rather than the libfdisk library). Parted determines the file system type by examining the actual file system written onto a partition, instead of relying on the file system type written in the partition table. This can lead to confusing situations when there are pre-existing partitions. For example, if you use fdisk to change the partition type of a VFAT partition to ext2, parted will still see this as a VFAT partition because there is still a VFAT file system on it. In this example, you must explicitly reformat the partition as ext2 via the Disk Druid interface before the partition will be treated as ext2. Any time you use fdisk inside the installer, and then proceed to the Disk Druid screen to set mount points, you should also review and edit each partition (in Disk Druid) and appropriately set its format options. Kickstart --------- - During the installation process, a kickstart file reflecting the user-selected installation options is written to /root/anaconda-ks.cfg. This file can be used to create an installation similar to the newly-installed system. - Kickstart runs in graphical mode (when this mode is available). However, it can be switched back to text mode by using the 'text' directive in the kickstart file. - Kickstart Configurator (ksconfig) supports creating partitions on a specific drive and an existing drive, configuring X, and writing pre-installation and post-installation scripts. It also allows users to preview their choices before saving the file, and has an integrated manual to assist in easy kickstart file creation. - Kickstart offers the following features/directives: interactive: Reads in kickstart file, fills in the installation UI with kickstart values, and waits for user input at each screen. text: Forces kickstart to run in text mode (default is graphical mode). - The clearpart directive accepts an --ondisk option which allows you to specify on which drives to create partitions. - The bootloader command supports the following options: --append : Append on the kernel line --useLilo: Use LILO instead of GRUB --md5pass : Password for GRUB to use - The xconfig directive supports the following: --resolution 1024x768: Set screen resolution (1024 by 768 in this example) --depth 16: Set display color depth (16-bit color in this example) MISCELLANEOUS ------------- - Support for upgrading to CentOS from a previous version of Red Hat Linux or CentOS is not included with this product. Refer to the following URL for more information: http://www.redhat.com/software/linux/advanced/ - The drivers.img driver disk image is delivered in multiple disk images. For more information, please read the README file in the images/ directory on CD #1 (or in the install tree you are using for network installs). - The individual package selection screen supports a flat view of all packages. - For FTP-based installations, it is possible to loopback mount the CentOS-2 ISO images on an FTP server. The ISO images should be loopback mounted as /disc1, /disc2, and so on, in the same directory. This directory should be then be specified when an FTP-based installation is started. - In order to maximize space in the install image, the BusyBox program provides support for many commonly-used commands. - Rescue mode prompts before attempting to mount file systems from the installed system. - USB floppy devices are supported during installation. KERNEL NOTES ------------ - The kernel includes the ext3 journaling file system, which has the following modes of operation: - ordered - journal - writeback The default is ordered, which will make sure that after a crash you should always see valid data in recently-written files. The writeback mode can be faster in some cases, but it does not force data to disk so rigorously; therefore, after a crash you may see corruption in recently-written files. The journal mode copies all data to the journal, and can result in great speed boosts if you are performing lots of synchronous data writes (for example, on mail spools or synchronous NFS servers). However, in normal use journal mode is usually significantly slower. The mode is set by using the 'data=' mount option in /etc/fstab or as 'mount -o data=' on the mount command line. Normally, an ext2 file system is checked automatically once either a certain period of time or a given number of mounts have passed since the file system was last checked. At these times, a full file system check (fsck) of the file system will be forced at system boot time in order to check the integrity of the file system. When the installer creates an ext3 file system or upgrades an ext2 file system to ext3, it disables these automatic checks. Use tune2fs with the -c and/or -i options to re-enable them, or to disable them on ext3 file systems that you create manually. Note that these cleanup fsck scans have nothing to do with the file system's behavior when an error is discovered on disk, or when a crash occurs. If a file system consistency error is found on disk, then on subsequent reboot a fsck will always be forced, both for ext2 and ext3 file systems. If a crash occurs on an otherwise intact file system, ext2 will always force a fsck, and ext3 will always perform its file system recovery step; these cleanups are not affected by the tune2fs forced-check interval settings. Please keep in mind that even a journaling file system can be damaged by power loss. When a system loses power, that system's behavior is undefined. For example, memory contents can decay (become randomly corrupt) as the contents are copied to a hard drive running on the last bit of power. This is a fundamentally different situation from the more defined sequence of events caused by pressing the system's reset button while the system is running. In addition, IDE hard drives do not provide all of the write order guarantees that SCSI drives do. Therefore, after a system crash, you will be offered a chance to choose to check the integrity of your file systems. The file /.autofsck is the crash flag used to provide this functionality. You will be given five seconds to type "y" to check your file systems during a boot after your system has crashed for any reason. - The netconsole kernel patch has been added to the core distribution. This patch will be incorporated in future releases of CentOS. The netconsole patch enables kernel-level logging over a network via UDP packets. Note that netconsole currently has limited network driver support. Refer to the netconsole/netdump whitepaper located at http://www.redhat.com/whitepapers for more information. - SCSI layer locking offers improved performance. - The POSIX aio_* asynchronous I/O functions provide kernel support. - When using RAID storage configured with Logical Unit Numbers (LUNs) greater than zero, it is necessary to enable LUN support by adding the following entry to the /etc/modules.conf file: options scsi_mod max_scsi_luns=255 After modifying modules.conf, it is necessary to rebuild the initial ramdisk using mkinitrd. Refer to The Official Red Hat Linux Customization Guide for more information about creating the ramdisk image with mkinitrd. - The linux-abi facility for running some binaries built for various versions of UNIX is not present in this release. PRINTING NOTES -------------- - The printconf system provides a printconf-tui program, for text-mode printer configuration. - The printconf-tui program provides command line import and export capabilities. The import can merge printer definitions with those that are already present, or it can override them (the default). Example: printconf-tui --Xexport > settings.xml printconf-tui --Ximport < settings.xml or: printconf-tui --Ximport --merge < settings.xml Combined with redirection -- such as bash's 'here documents' (see the bash man page for more information) -- you can easily put printer setups into kickstart files. - The printconf-tui program can clear settings completely. Example: printconf-tui --Xclear - The printconf tools provide limited printer auto-detection. - redhat-config-printer-tui and redhat-config-printer-gui alias printconf-tui and printconf-gui, respectively. - Ghostscript 6.51 is available with this release, and supports many additional drivers, as well as encrypted PDF files. - Support is provided for Hewlett Packard hpijs ghostscript print drivers. Although they are not shipped with CentOS-2, you can download these drivers from the project site at: http://hpinkjet.sourceforge.net The ghostscript print drivers should work as drop-in components. DRIVER UPDATES -------------- This release includes several new and updated drivers. In cases where the update represents a significant change to the driver, such as a driver re-write, the new driver has been added to the system with a different name, and the original driver has been preserved. This allows those who do not need the features of the new driver, or who prefer not to make a change at this time, to continue to use the old driver. Drivers that have been updated in-place (not renamed) are described in this section. New drivers that have been added with an alternate name are described in the section "Alternate Drivers". - LSI Logic MPT Fusion (mpt* drivers) Version 2.02.01 of the MPT Fusion drivers is included with this release. These drivers provide new support for FC919X and FC929X adapters, and provide various bug fixes. - LSI Logic (AMI) RAID (megaraid driver) Support for the MegaRAID Elite 1650 adapter is available with v1.18, which is included with this release. A new, substantially re-written MegaRAID driver with additional hardware support is also available, as described in the section "Alternate Drivers". - 3ware (3w-xxx driver) Version 1.02.00.27 of the 3ware driver is included in this release. This version adds support for the 8500 series of adapters, and provides various bug fixes. - Adaptec RAID (aacraid driver) The aacraid driver in this release provides performance and stability enhancements. This driver also adds support for the following adapter models: - Adaptec "catapult", "tomcat", 2120S (Crusader, Vulcan, Vulcan-2m), 5400S (Mustang) - Dell PERC 320/DC - Broadcom Tigon3 (tg3 driver) The Broadcom Tigon3 supports netdump and adds support for the the ALTIMA_AC9100. NOTE: A newer version of the tg3 driver (also with netdump support) is available, as described in the section "Alternate Drivers". - Intel ICP vortex RAID (gdth driver) A bug in scsi.c that could cause an oops in the gdth driver was fixed. - Intel i810 Audio (i810_audio driver) The driver version has been updated from 0.21 to 0.24 to add support for new hardware and other enhancements. The new hardware includes: Intel ICH4, Nvidia MCP2, MCP3, AMD 768, 8111_AC97. - Silicon Integrated System LAN (sis900_new driver) The default driver for the sis900 family of HBAs is drivers/net/sis900, version 1.07.11. A newer version is available, called drivers/net/sis900_new. This release includes sis900_new version 1.08.06, which adds support for the SIS96x adapters, and various bug fixes. - SCSI drivers - The number of SCSI disks that can be configured is at least 128. - The system will not issue a SCSI start command to logical units that indicate they require manual intervention to become ready. This eliminates unnecessary long delays when configuring these devices. - A performance problem involving SCSI requests consisting of a single segment and multiple buffer headers has been fixed. - Additions have been made to the list of SCSI devices that require special handling during configuration. Alternate Drivers ----------------- This release contains several alternate drivers that provide new hardware support and improvements. These drivers are provided as alternates because each is substantially different from the corresponding original driver, and some users may prefer to continue running the original driver at this time. - Qlogic Fibre Channel (qla2xxx driver) A newer version of the driver for the Qlogic QLA2100, QLA2200, and QLA2300 adapters is included in this release. This driver solves problems that were encountered with the earlier driver when configuring certain FC topologies and FC devices. The new drivers are version 6.03.00, located in /drivers/addon/qla2xxx_60300, and are named qla2100_60300.o qla2200_60300.o qla2300_60300.o - LSI Logic (AMI) RAID (megaraid driver) A newer version of the driver for the LSI Logic MegaRAID family of adapters is included in this release. This driver supports additional adapter models, and provides various problem fixes. The new adapter models are the DISCOVERY (0x000E), PERC4_DI (0x000F), and PERC4_QC_VERDE (0x0407). The new driver is version 2.00.2, located in drivers/addon/megaraid_2001/megaraid_2001.o. - IBM ServeRAID (ips driver) A newer version of the driver for the ServeRAID family of adapters is included in this release. This driver adds support for the 5i RAID controller, and includes various problem fixes. The default ips driver in CentOS-2 is 4.80.26. The newer version is 5.10.21, located in drivers/addon/ips_51021/ips_51021.o. Note that the firmware version on the adapter must match the driver version. Update your adapter firmware before switching to this new driver. - Intel PRO/100 (e100 driver) The e100 driver is an alternative to the eepro100 driver. The e100 may work better than the eepro100 on some hardware. This release provides two versions of the e100 driver. One is the default CentOS-2 version (1.6.22), located in drivers/addon/e100.o. The other is a new version (2.1.24-k2), located in drivers/addon/e100_2124k2/e100_2124k2.o. - Intel PRO/1000 (e1000 driver) A newer version of the e1000 driver, for the PRO/1000 family of adapters, is included in this release. This driver supports additional adapter models, and fixes several problems. The default e1000 driver in CentOS is 3.1.23. The newer version is 4.4.12-k1, located in drivers/addon/e1000_4412k1/e1000_4412k1.o. - Broadcom Tigon3 (tg3 driver) A newer version of the tg3 driver, for the Broadcom Tigon3 family of adapters, is included in this release. This driver supports the 5704 adapter models, and fixes several problems. The newer version is 1.2e3, located in drivers/addon/tg3_12e1/tg3_12e1.o. This release provides netdump support for both the original tg3 and for the new tg3_12e3. - AMD PCnet32 and PCnetPCI (pcnet32 driver) A newer version of the pcnet32 driver, for the AMD PCnet32 and PCnetPCI family of adapters, is included in this release. This driver fixes several problems. The default version in CentOS-2 is v1.25kf. The newer version, 1.27b, is located in drivers/addon/pcnet32_127b.o - Silicon Integrated System LAN (sis900_new driver) The default driver for the sis900 family of HBAs is drivers/net/sis900, version 1.07.11. A newer version, (1.08.06) is available, located in drivers/net/sis900_new. Some older models of sis900 adapters operate better with the default driver. Newer sis900 models may operate better with the newer driver. - Adaptec SCSI Adapters The default driver for the Adaptec family of HBAs is driver/scsi/aic7xxx.o, version 5.2.5. A newer version (6.2.8) is available, located in driver/scsi/aic7xxx_mod.o. Some older models of Adaptec adapters operate better with the default driver. Newer Adaptec models may operate better with the newer driver. How to Use an Alternate Driver ------------------------------ If it becomes necessary to change from the standard driver to an alternate driver, follow these steps: 1. Edit /etc/modules.conf and replace each occurrence of the standard driver name with the alternate driver name. For example, the line: alias scsi_hostadapter4 qla2200 would become: alias scsi_hostadapter4 qla2200_60300 2. Re-make the initial RAM disk, with commands similar to the following, substituting the version number (for example, 2.4.9-e.11) of the current kernel for : cd /boot mv initrd-.img initrd-.img-saved mkinitrd initrd-.img 3 . If you are using LILO, then run LILO and reboot. If you are running GRUB, just reboot.