mirror of
git://sourceware.org/git/lvm2.git
synced 2024-10-28 20:25:52 +03:00
LVM2 mirror repository
https://sourceware.org/lvm2/
3501f17fd0
A while back, the behavior of LVM changed from allowing metadata changes when PVs were missing to not allowing changes. Until recently, this change was tolerated by HA-LVM by forcing a 'vgreduce --removemissing' before trying (again) to add tags to an LV and then activate it. LVM mirroring requires that failed devices are removed anyway, so this was largely harmless. However, RAID LVs do not require devices to be removed from the array in order to be activated. In fact, in an HA-LVM environment this would be very undesirable. Device failures in such an environment can often be transient and it would be much better to restore the device to the array than synchronize an entirely new device. There are two methods that can be used to setup an HA-LVM environment: "clvm" or "tagging". For RAID LVs, "clvm" is out of the question because RAID LVs are not supported in clustered VGs - not even in an exclusively activated manner. That leaves "tagging". HA-LVM uses tagging - coupled with 'volume_list' - to ensure that only one machine can have an LV active at a time. If updates are not allowed when a PV is missing, it is impossible to add or remove tags to allow for activation. This removes one of the most basic functionalities of HA-LVM - site redundancy. If mirroring or RAID is used to replicate the storage in two data centers and one of them goes down, a server and a storage device are lost. When the service fails-over to the alternate site, the VG will be "partial". Unable to add a tag to the VG/LV, the RAID device will be unable to activate. The solution is to allow vgchange and lvchange to alter the LVM metadata for a limited set of options - --[add|del]tag included. The set of allowable options are ones that do not cause changes to the DM kernel target (like --resync would) or could alter the structure of the LV (like allocation or conversion). |
||
|---|---|---|
| autoconf | ||
| daemons | ||
| doc | ||
| include | ||
| lib | ||
| libdaemon | ||
| libdm | ||
| liblvm | ||
| man | ||
| old-tests | ||
| po | ||
| report-generators | ||
| reports | ||
| scripts | ||
| test | ||
| tools | ||
| udev | ||
| unit-tests | ||
| .gitignore | ||
| aclocal.m4 | ||
| configure | ||
| configure.in | ||
| COPYING | ||
| COPYING.LIB | ||
| INSTALL | ||
| make.tmpl.in | ||
| Makefile.in | ||
| README | ||
| VERSION | ||
| VERSION_DM | ||
| WHATS_NEW | ||
| WHATS_NEW_DM | ||
This tree contains the LVM2 and device-mapper tools and libraries. For more information about LVM2 read the changelog in the WHATS_NEW file. Installation instructions are in INSTALL. There is no warranty - see COPYING and COPYING.LIB. Tarballs are available from: ftp://sources.redhat.com/pub/lvm2/ The source code is stored in git: http://git.fedorahosted.org/git/lvm2.git git clone git://git.fedorahosted.org/git/lvm2.git Mailing list for general discussion related to LVM2: linux-lvm@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/linux-lvm Mailing lists for LVM2 development, patches and commits: lvm-devel@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/linux-lvm lvm2-commits@lists.fedorahosted.org (Read-only archive of commits) Subscribe from https://fedorahosted.org/mailman/listinfo/lvm2-commits Mailing list for device-mapper development, including kernel patches and multipath-tools: dm-devel@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/dm-devel The source code repository used until 7th June 2012 is accessible here: http://sources.redhat.com/cgi-bin/cvsweb.cgi/LVM2/?cvsroot=lvm2.