Friday 14th November 2003 ========================= Some bug fixes & minor enhancements, including: Backwards compatibility with LVM1 metadata improved. Missing man pages written. Tool error codes made more consistent. vgmknodes written. O_DIRECT can be turned off if it doesn't work in your kernel. dumpconfig to display the active configuration file You need to update libdevmapper before using 'vgmknodes' or 'vgscan --mknodes'. If your root filesystem is on an LV, you should run one of those two commands to fix up the special files in /dev in your real root filesystem after finishing with your initrd. Also, remember you can use 'vgchange --ignorelockingfailure' on your initrd if the tool fails because it can't write a lock file to a read-only filesystem. Wednesday 30th April 2003 ========================= A pvmove implementation is now available for the new metadata format. When running a command that allocates space (e.g. lvcreate), you can now restrict not only which disk(s) may be used but also the Physical Extents on those disks. e.g. lvcreate -L 10 vg1 /dev/hda6:1000-2000:3000-4000 Monday 18th November 2002 ======================== The new format of LVM metadata is ready for you to test! We expect it to be more efficient and more robust than the original format. It's more compact and supports transactional changes and replication. Should things go wrong on a system, it's human-readable (and editable). Please report any problems you find to the mailing list, linux-lvm@sistina.com. The software has NOT yet been thoroughly tested and so quite possibly there'll still be some bugs in it. Be aware of the disclaimer in the COPYING file. While testing, we recommend turning logging on in the configuration file to provide us with diagnostic information: log { file="/tmp/lvm2.log" level=7 activation=1 } You should schedule regular backups of your configuration file and metadata backups and archives (normally kept under /etc/lvm). Please read docs/example.conf and "man lvm.conf" to find out more about the configuration file. To convert an existing volume group called vg1 to the new format using the default settings, use "vgconvert -M2 vg1". See "man vgconvert". -M (or --metadatatype in its long form) is a new flag to indicate which format of metadata the command should use for anything it creates. Currently, the valid types are "lvm1" and "lvm2" and they can be abbreviated to "1" and "2" respectively. The default value for this flag can be changed in the global section in the config file. Backwards-compatible support for the original LVM1 metadata format is maintained, but it can be moved into a shared library or removed completely with configure's --with-lvm1 option. Under LVM2, the basic unit of metadata is the volume group. Different volume groups can use different formats of metadata - vg1 could use the original LVM1 format while vg2 used the new format - but you can't mix formats within a volume group. So to add a PV to an LVM2-format volume group you must run "pvcreate -M2" on it, followed by "vgextend". With LVM2-format metadata, lvextend will let you specify striping parameters. So an LV could consist of two or more "segments" - the first segment could have 3 stripes while the second segment has just 2. LVM2 maintains a backup of the current metadata for each volume group in /etc/lvm/backup, and puts copies of previous versions in /etc/lvm/archive. "vgcfgbackup" and "vgcfgrestore" can be used to create and restore from these files. If you fully understand what you're doing, metadata can be changed by editing a copy of a current backup file and using vgcfgrestore to reload it. Please read the pvcreate man page for more information on the new format for metadata. All tools that can change things have a --test flag which can be used to check the effect of a set of cmdline args without really making the changes. What's not finished? ==================== The internal cache. If you turn on debugging output you'll see lots of repeated messages, many of which will eventually get optimised out. --test sometimes causes a command to fail (e.g. vgconvert --test) even though the real command would work: again, fixing this is waiting for the work on the cache. Several of the tools do not yet contain the logic to handle full recovery: combinations of pvcreate and vgcfgrestore may sometimes be needed to restore metadata if a tool gets interrupted or crashes or finds something unexpected. This applies particularly to tools that work on more than one volume group at once (e.g. vgsplit). Display output. Some metadata information cannot yet be displayed. Recovery tools to salvage "lost" metadata directly from the disks: but we hope the new format will mean such tools are hardly ever needed!