These release notes document known issues with Ubuntu 10.04 LTS and its variants.  

The minimum memory requirement for Ubuntu 10.04 LTS is 256 MB of memory. Note that some of your system's memory may be unavailable due to being used by the graphics card. If your computer has only the minimum amount of memory, the installation process will take longer than normal, but will complete successfully, and the system will perform adequately once installed.   

Systems with less memory may be able to select "Install Ubuntu" from the boot menu to run just the installer, rather than the whole desktop, or may be able to use the alternate install CD.   

A separate page has been made available with release notes for the developer-oriented Ubuntu 10.04 armel port. Please see https://wiki.ubuntu.com/ARM/LucidReleaseNotes for information about issues affecting installation on ARM.   

The default file system for installations of Ubuntu 10.04 LTS is ext4, the latest version in the popular series of Linux extended file systems. ext4 includes a number of performance tuning changes relative to previous versions such as ext3, the file system used by default up to Ubuntu 9.04. These generally produce improvements, but some particular workloads are known to be significantly slower when using ext4 than when using ext3. If you have performance-sensitive applications, we recommend that you run benchmarks using multiple file systems in your environment and select the most appropriate.   

In particular, the dpkg package manager is known to run significantly slower on ext4, causing installations using the server or alternate install CD to take on the order of twice as long as before. ext4 does not guarantee atomic renames of new files over existing files in the event of a power failure shortly after the rename, and so dpkg needs to force the contents of the new file out to disk before renaming it in order to avoid leaving corrupt zero-length files after power failures. This operation involves waiting for the disk significantly more than it strictly needs to, and so degrades performance. If fast package management operations are most important to you, then you should use ext3 instead. (570805)   

The simplest way to select a different file system such as ext3 at installation time is to add the partman/default_filesystem=ext3 boot parameter when starting the installer. If you are deploying Ubuntu automatically using Kickstart or preseeding, then you can set a different file system in the partitioning recipe instead.   

In accordance with the Debian Policy Manual (which says "The 'Recommends' field should list packages that would be found together with this one in all but unusual installations"), the package management system now installs packages listed in the Recommends: field of other installed packages as well as Depends: by default. If you want to avoid this for specific packages, use apt-get --no-install-recommends; if you want to make this permanent, set APT::Install-Recommends "false"; in /etc/apt/apt.conf. Be aware that this may result in missing features in some programs.   

(This change was made in Ubuntu 8.10.)   

The default partitioning recipe in the installer will in some cases allocate a swap partition that is smaller than the physical memory in the system. This will prevent the use of hibernation (suspend-to-disk) because the system image will not fit in the swap partition. If you intend to use hibernation with your system, you should ensure that the swap partition's size is at least as large as the system's physical RAM. (345126)   

In some cases, ejecting the CD at the end of installation will leave errors on the screen such as:   

these error messages indicate that the system is still trying to access some files on the CD, and are harmless except that they obscure the message asking the user to press Enter to reboot. You can safely remove the CD from the tray and press Enter at this point to reboot to your new Ubuntu system. (539027)   

The Ubuntu 10.04 LTS Desktop and Netbook CDs feature a new boot interface that is noninteractive by default. To configure advanced boot options, press any key at the first boot screen.   

A bug in migration-assistant prevents some users with separate home partitions from completing the install successfully. Users who experience such a crash can disable migration-assistant by selecting "Try Ubuntu" at the first screen of the installer, then pressing Alt-F2 and typing ubiquity --no-migration-assistant at the prompt that appears. (536673)   

Dmraid "fake raid" devices are supported out-of-the-box on the Ubuntu 10.04 LTS Desktop CD, and are detected and activated by dmraid on boot. Ubiquity will offer to install on the RAID array, and not on the RAID members.   

The automatic activation of dmraid can be disabled with the "nodmraid" boot option, available by pressing F6 in the CD boot menu. This can be useful for setups which have fakeraid metadata present on the disks, but where dmraid activation would be undesired or cause problems.   

By default, Ubuntu 10.04 LTS aligns partitions on disk to 1 MiB (1048576 bytes) boundaries. This ensures maximum performance on many modern disks, particularly solid state drives but also new "Advanced Format" disks with physical sectors larger than the traditional 512 bytes. Very few systems nowadays need the old alignment, used in the days of MS-DOS when it was useful for partitions to start at the beginning of a cylinder.   

In some rare cases, optimal alignment may cause problems. Some BIOS implementations (those on Asus P5P800-MX and Asus P5GZ-MX motherboards) have been reported to hang after installation. It may be difficult to install Microsoft Windows XP and older after installing Ubuntu, although more recent versions of Windows should be compatible with optimal alignment and indeed may produce it themselves. If you find that you need to use the old cylinder alignment instead, then add the partman/alignment=cylinder boot parameter when starting the installer. (551965)   

On some machines, the CD boot fails with the message "The installer encountered an unrecoverable error. A desktop session will now be run so that you may investigate the problem or try installing again." If you encounter this error, restart your computer with the CD inserted, press any key at the splash screen (when you see the keyboard icon at the bottom of the screen), and select "Try Ubuntu without installing". Once the desktop appears, use the "Install Ubuntu 10.04" icon to begin installing Ubuntu. (567899)   

Users of Ubuntu 9.10 and Ubuntu 8.04 LTS can upgrade to Ubuntu 10.04 by a convenient automated process. Users of other Ubuntu releases need to upgrade first to either Ubuntu 8.04 LTS or Ubuntu 9.10, and then to 10.04. Complete instructions may be found at http://www.ubuntu.com/getubuntu/upgrading.   

If you have previously modified the menu.lst bootloader configuration for GRUB, either by hand or with a tool such as kgrubeditor, you may be asked on upgrade whether you wish to keep your local version of the menu.lst or install the package maintainer's version. This question is asked because such changes cannot be merged automatically with 100% reliability, and care is taken to not overwrite the user's manually edited bootloader configuration without warning.   

However, if you choose to "keep the local version currently installed," your system will not be set up to boot from any newly-installed kernels. Manual action is required on your part to ensure that your system is running the current, security-supported kernel after upgrade. If you have local changes to your bootloader config that you want to keep, it is recommended that you follow these steps:   

• Choose "keep the local version currently installed" at the prompt.  

• Open /boot/grub/menu.lst with a text editor (e.g., sudo gedit /boot/grub/menu.lst).  

• Apply any changes you've made to the kernel boot options to the commented variables (e.g., groot, kopt, defoptions) above.   

• Move any manually-added boot options for other operating systems so that they are above the line   

  ### BEGIN AUTOMAGIC KERNELS LIST

  or below the line   

  ### END DEBIAN AUTOMAGIC KERNELS LIST  

• Save the file, and run sudo update-grub from the commandline.  

• Choose "install the package maintainer's version".   

For example, if you added an option i915.modeset=0 to the "kernel" line:   

then add this option to kopt:   

An updated version of the grub package will include information about this problem in the help screen for the menu.lst prompt. (470490)    

Ubuntu 10.04 LTS enables the CRDA wireless regulatory framework for controlling which wireless channels are usable and visible in a particular location. If you previously had to use the module option similar to that below in /etc/modprobe.d/options.conf to allow access to certain channels in your locality then you may find that wireless will not function at all:   

• options cfg80211 ieee80211_regdom=EU   

You should remove this kernel module option on upgrade from releases earlier than Ubuntu 9.04 and use the iw reg command instead.   

(This change was made in Ubuntu 9.04.)   

The migration of network handling to upstart means that all network devices are now handled in a hotplug manner. As a result, bonded interfaces are only brought up reliably on boot when the bonded interface is created as part of the configuration of the physical interface; otherwise, the system may attempt to bring up the bonded interface before the underlying physical interfaces are available, and fail. For an example of how to configure a bonding interface for hotplug, please see /usr/share/doc/ifenslave-2.6/examples/two_hotplug_ethernet in the ifenslave-2.6 package.   

(This change was made in Ubuntu 9.10.)   

The kubuntu upgrade may leave the no longer needed packages "kde-guidance-powermanager" or "guidance-power-manager" installed. Those can be removed.   

Akonadi startup is sometimes faulty preventing access to the address book and other resources. To work around this, close and restart Kontact. (564263)   

Since Ubuntu 9.04, the Ctrl-Alt-Backspace key combination to force a restart of X is now disabled by default, to eliminate the problem of accidentally triggering the key combination. In addition, the Ctrl-Alt-Backspace option is now configured as an X keymap (XKB) option, replacing the X server "DontZap" option and allowing per-user configuration of this setting.   

As a result, enabling or disabling the Ctrl+Alt+Backspace shortcut can now be done easily from the desktop.   

Enabling Ctrl-Alt-Backspace for Ubuntu

• Select "System"->"Preferences"->"Keyboard"  

• Select the "Layouts" tab and click on the "Layout Options" button.  
• Select "Key sequence to kill the X server" and enable "Control + Alt + Backspace".   

Enabling Ctrl-Alt-Backspace for Kubuntu

• Click on the Application launcher and select "System Settings"  

• Click on "Regional & Language".  

• Select "Keyboard Layout".  
• Click on "Enable keyboard layouts" (in the Layout tab).  
• Select the "Advanced" tab. Then select "Key sequence to kill the X server" and enable "Control + Alt + Backspace".   

For further information, see: https://wiki.ubuntu.com/X/Config/DontZap   

Ubuntu 10.04 LTS launches update-manager directly to handle package updates, instead of displaying a notification icon in the GNOME panel. Users are notified of security updates on a daily basis, but for updates that are not security-related, users will only be prompted once a week.   

Users who wish to continue receiving update notifications in the previous manner can restore the earlier behavior using the following command:   

(This change was made in Ubuntu 9.04.)   

In Ubuntu 10.04 LTS, MySQL 5.1 is the only version of MySQL available. Performing an upgrade via update-manager will correctly handle the transition from MySQL 5.0 to MySQL 5.1.   

MySQL Cluster setup

If MySQL has been set up to use the MySQL Cluster engine (NDB engine), upgrading to MySQL 5.1 will not work since the mysql-dfsg-5.1 packages don't support MySQL Cluster. Instead the mysql-cluster-server package should be installed.   

The version of upstart included in Ubuntu 10.04 LTS no longer uses the configuration files in the /etc/event.d directory, looking to /etc/init instead. No automatic migration of changes to /etc/event.d is possible. If you have modified any settings in this directory, you will need to reapply them to /etc/init in the new configuration format by hand. (402759)   

(This change was made in Ubuntu 9.10.)   

The sysklogd package has been replaced with rsyslog. Configurations in /etc/syslog.conf will be automatically migrated to /etc/rsyslog.d/50-default. If you modified the log rotation settings in /etc/cron.daily/sysklogd or /etc/cron.weekly/sysklogd, you will need to change the new configurations in /etc/logrotate.d/rsyslog. Also note that the prior rotation configurations used .0 as the first rotated file extension, and now with logrotate it will be .1.   

(This change was made in Ubuntu 9.10.)   

Users who had installed pre-release versions of Ubuntu 9.10 may have corrupted OpenOffice.org service or component registry files on their system as a result of a bug in version 1:3.1.1-14 of the OpenOffice.org packages. If you experience segfaults in either unopkg or OpenOffice.org after upgrade, you may need to remove and regenerate the registry files in /var/lib/openoffice/basis3.2/program/ and /var/spool/openoffice/uno_packages/cache. (546797)   

The lpia architecture present in previous releases has been discontinued as of Ubuntu 10.04 LTS. The hardware is still supported, but systems that were installed as lpia will need to be backed up and reinstalled from scratch using either the i386 or amd64 architectures. See bug 523295, which includes an unsupported method for migration from lpia to i386.

The "cmusieve" plugin used in dovecot has been renamed to "sieve". Users who have the following set in their dovecot configuration:

should change this to:

If you installed Lucid prior to Alpha 3, you may have libmysqlclient16 7.0.9-1 installed. This package was present in the Ubuntu archive by mistake and was retracted, but because it has a later version number than the real libmysqlclient16 package, the real package will not be installed automatically on upgrade. To ensure that you have the official package installed on your Lucid system and will receive security support for it throughout Ubuntu 10.04 LTS, it is important that you run sudo apt-get install libmysqlclient16/lucid and follow the instructions. (522225)

If you choose to upgrade your / or /boot filesystem in place from ext2 or ext3 to ext4 (as documented on the ext4 wiki), then you must also use the grub-install command after upgrading to Ubuntu 10.04 LTS to reinstall your boot loader. If you do not do this, then the version of GRUB installed in your boot sector will not be able to read the kernel from the ext4 filesystem and your system will fail to boot.

Upstart jobs cannot be started in a chroot because upstart acts as a service supervisor, and processes within the chroot are unable to communicate with the upstart running outside of the chroot (430224). This will cause some packages that have been converted to use upstart jobs instead of init scripts to fail to upgrade within a chroot. Users are advised to configure their chroots with /sbin/initctl pointing to /bin/true, with the following commands run within the chroot:

If each member of a RAID 1 array is separately brought up in degraded mode across subsequent runs of the array with no reassembly in between, there is a risk that the disks will be reported as in sync when they are not, resulting in data loss due to inconsistencies between the data that has been written to each member. This is an unlikely occurrence during normal operations, but admins of systems using RAID 1 arrays should take care during maintenance to avoid this situation. (557429)

Users who have configured any encrypted partitions in /etc/crypttab to start at boot time (i.e., not using the noauto option) should make sure that the filesystems on these volumes are listed in /etc/fstab. Otherwise, the passphrase prompt is not guaranteed to be displayed at boot time.

In general, filesystems are listed in /etc/fstab by UUID rather than by device name, to ensure that the filesystem can always be found reliably. If you are mounting a filesystem located on LVM, however, it is recommended that you list them in /etc/fstab by device name, not by UUID, because UUIDs are not unique if LVM snapshots are used, which can result in wrong filesystems being mounted at boot. (563902)

The linux kernel packages for the ia64, powerpc, and sparc architectures builds device-mapper support as a module, where the packages for the other architectures have the driver built in, which leads to boot failures on ia64/powerpc/sparc when using LVM. To work around this, users must run these commands manually from the initramfs:

This issue will be addressed in a post-release kernel update. (560717)

The avahi-daemon package, which implements the mDNS "zeroconf" standard, formerly included a check to avoid running when a conflicting .local DNS domain is present, as it was reported that some ISPs advertise such a .local domain on their networks, leaving Ubuntu hosts unable to see names advertised on the local network (327362). In Ubuntu 9.10, avahi-daemon is started regardless.

It is possible that this may cause other problems. If your network is configured this way, you can disable mDNS using the following command:

Ubuntu 10.04 LTS enables the new kernel-mode-setting (KMS) technology by default on most common video chipsets. While this is a major step forward for the graphics architecture in Ubuntu, in some rare cases KMS will prevent your video output from working correctly, or from working at all. If you need to disable KMS, you can do so by booting with the nomodeset option. You can also save this setting so that it's applied at every boot by adding it to your grub config (for GRUB 2: edit /etc/default/grub and add nomodeset to GRUB_CMDLINE_LINUX, then run sudo update-grub; for GRUB 1: edit /boot/grub/menu.lst and add nomodeset to the line beginning with # kopt=, then run sudo update-grub). (533784, 541501)

Evince, the GNOME document viewer, now ships with an enforcing AppArmor profile. This greatly increases security by protecting users against flaws in the historically problematic PDF and image libraries. Users who use a non-standard location for their home directory will need to adjust the home tunable in /etc/apparmor.d/tunables/home. See https://wiki.ubuntu.com/DebuggingApparmor#Adjusting%20Tunables for details.

When using the GRUB 2 bootloader included in Ubuntu 10.04 LTS, the first boot option will by default be loaded automatically without pausing for user input. To interrupt the boot, users can hold down the Shift key to bring up the boot menu, allowing them to select a different boot option or to configure kernel arguments. (https://help.ubuntu.com/community/Grub2#GRUB%20vs%20GRUB%202)

With the introduction of plymouth, boot-time messages from startup scripts are no longer displayed above the login prompt on tty1. Instead, they are all output to tty7 and on Ubuntu Server, can be viewed after boot by pressing Alt+F7. On all systems the boot output can also be found in /var/log/boot.log.

On new installs of Ubuntu 10.04 LTS Server, no boot splash screen is shown by default. While this provides server administrators with more immediate feedback about their system while booting, it also prevents prompts from reaching the user in the event of filesystem mounting failures. Users can add the splash option to /etc/default/grub if they prefer to always see the splash screen. Hotkeys for interacting with mountall will still work without the splash screen, but are not discoverable: C to cancel a running fsck; M to request a maintenance shell; S to skip an unavailable mount; and F to try to fix errors found by a fsck. (563916)

Upgrading systems configured to use LDAP via SSL as the first service in the NSS stack (in /etc/nsswitch.conf) leads to broken NSS resolution afterwards such that setuid applications like sudo would stop working. To work around this, switch to the libnss-ldapd package instead of libnss-ldap before the upgrade, or use nscd. (423252)

When upgrading some systems from Karmic or pre-release versions of Lucid, OpenLDAP may fail to start by logging messages similar to "ordered_value_sort failed on attr olcAccess#012". To workaround the problem remove the line "olcAccess: to * by dn.exact=cn=localroot,cn=config manage by * break" from /etc/ldap/slapd.d/cn=config/olcDatabase={-1}frontend.ldif and /etc/ldap/slapd./cn=config/olcDatabase={0}config.ldif. An update fixing this automatically should be available soon after release. (571057)

For Ubuntu 10.04 LTS, the sun-java6 packages have been dropped from the Multiverse section of the Ubuntu archive. It is recommended that you use openjdk-6 instead.

If you can not switch from the proprietary Sun JDK/JRE to OpenJDK, you can install sun-java6 packages from the Canonical Partner Repository. You can configure your system to use this repository via command-line:

With older ATI graphics cards with 32MB or less of video RAM some corruption of direct rendered windows, for example OSD notifier windows, might appear. This may be worked around by disabling 'RenderAccel' in the Xorg configuration. (426582)

To do this first exit to the console using the following command:

• sudo service gdm stop

Then create an Xorg configuration file with the command below:

• sudo Xorg -configure

Then add the 'RenderAccel' option to /etc/X11/xorg.conf:

• Section "Device"
  ...
  Driver "radeon"
  Option "RenderAccel" "off"
  EndSection

And restart X/GDM.

Ubuntu 10.04 LTS includes improved integration for nVidia binary driver packages. Unfortunately, this comes at the expense of compatibility with the installer provided upstream on the nVidia website. Users who wish to use the nVidia binary video drivers with 10.04 LTS should install them using the Ubuntu packages, as made available under System -> Administration -> Hardware Drivers.

The -intel driver fails with X freezes or crashes on certain i8xx hardware. The issue is known upstream but solutions are still under development. For now, to work around the issue, boot with the -vesa video driver. See http://wiki.ubuntu.com/X/Bugs/Lucidi8xxFreezes for further details.

A bug in the AbiWord package in Ubuntu causes the application to hang whenever accessing the help interface, either from the menu or by pressing F1. Until this bug is fixed, users should avoid pressing F1 in AbiWord. (519541)

The Thunderbird mail and news client has been upgraded to version 3, but the "Lightning" calendar extension is not yet available for this version. We hope to provide a backport soon. (532232)