[[PageOutline]] * [http://www.usupi.org/sysad/166.html LVM のスナップショット機能を使ってみる - いますぐ実践! Linuxシステム管理 / Vol.166] * [http://www.atmarkit.co.jp/flinux/rensai/root06/root06a.html ＠IT：LVMによる自動バックアップ・システムの構築（1/3）] * [http://www.drbd.org/users-guide/ch-lvm.html Chapter 11. Using LVM with DRBD] * [http://www.drbd.jp/users-guide/ch-lvm.html 第11章 DRBDとLVMの使用] * [http://thinkit.co.jp/free/compare/5/9/ ThinkIT 第9回：バックアップにおけるスナップショットの活用 (1/3)] * [http://okkun-lab.rd.fukuoka-u.ac.jp/wiki/?Tips%2FLinux%2FLVM Tips/Linux/LVM - 福岡大学奥村研究室 - okkun-lab Pukiwiki!] * [http://pc.watanet.com/lab/homesvr/linux/lvm_resize/lvm_resize.html LVMパーティションの拡張] * arch:LVM そこそこ詳しい * https://wiki.gentoo.org/wiki/LVM 非常に良くまとまっている = lvchange/vgchange -ay = * root@Knoppix:~# vgdisplay -v {{{ Finding all volume groups Finding volume group "vgnfs" --- Volume group --- VG Name vgnfs System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 1.94 GB PE Size 32.00 MB Total PE 62 Alloc PE / Size 48 / 1.50 GB Free PE / Size 14 / 448.00 MB VG UUID I6vVoh-6gCJ-9uvA-v2MV-Fyva-7J8v-Cvftfi --- Logical volume --- LV Name /dev/vgnfs/drbd VG Name vgnfs LV UUID dNxdNj-hZCZ-GMrC-woMk-0hA2-f3oR-sBsrHI LV Write Access read/write LV Status NOT available LV Size 1.50 GB Current LE 48 Segments 1 Allocation inherit Read ahead sectors 0 --- Physical volumes --- PV Name /dev/md0 PV UUID Z2JXRP-fa5g-SYS5-xzMs-Lq8C-1Jbh-QPKihr PV Status allocatable Total PE / Free PE 62 / 14 }}} * LV is "NOT available" * lvchange -ay / vgchange -ay によってavailableにする * root@Knoppix:~# lvchange -ay /dev/vgnfs/drbd * root@Knoppix:~# vgchange -ay {{{ 1 logical volume(s) in volume group "vgnfs" now active }}} * [http://www.youchikurin.com/blog/2007/07/debian_1.html Debianのリカバリー (ゆうちくりんの忘却禄)] * root@Knoppix:~# vgdisplay -v {{{ Finding all volume groups Finding volume group "vgnfs" --- Volume group --- VG Name vgnfs System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 1.94 GB PE Size 32.00 MB Total PE 62 Alloc PE / Size 48 / 1.50 GB Free PE / Size 14 / 448.00 MB VG UUID I6vVoh-6gCJ-9uvA-v2MV-Fyva-7J8v-Cvftfi --- Logical volume --- LV Name /dev/vgnfs/drbd VG Name vgnfs LV UUID dNxdNj-hZCZ-GMrC-woMk-0hA2-f3oR-sBsrHI LV Write Access read/write LV Status available # open 0 LV Size 1.50 GB Current LE 48 Segments 1 Allocation inherit Read ahead sectors 0 Block device 254:0 --- Physical volumes --- PV Name /dev/md0 PV UUID Z2JXRP-fa5g-SYS5-xzMs-Lq8C-1Jbh-QPKihr PV Status allocatable Total PE / Free PE 62 / 14 }}} = Can't deactivate = * Shutting down LVM Volume Groups Can't deactivate volume group "vgroot" with 1 open logical volumes(s) failed! [[br]][[Image(deactivate.png,33%)]] * Debian 6.0 with 2.6.39-bpo.2-amd64 * lvm2: 2.02.66-5 * mitty@shizuku-debian:~$ ls /etc/rc6.d/ -l {{{ lrwxrwxrwx 1 root root 21 Oct 22 16:11 K01mpt-statusd -> ../init.d/mpt-statusd lrwxrwxrwx 1 root root 17 Oct 22 16:07 K01urandom -> ../init.d/urandom lrwxrwxrwx 1 root root 18 Oct 22 16:11 K02sendsigs -> ../init.d/sendsigs lrwxrwxrwx 1 root root 17 Oct 22 16:11 K03rsyslog -> ../init.d/rsyslog lrwxrwxrwx 1 root root 20 Oct 22 16:11 K04hwclock.sh -> ../init.d/hwclock.sh lrwxrwxrwx 1 root root 22 Oct 22 16:11 K04umountnfs.sh -> ../init.d/umountnfs.sh lrwxrwxrwx 1 root root 20 Oct 22 16:11 K05networking -> ../init.d/networking lrwxrwxrwx 1 root root 18 Oct 22 16:11 K06ifupdown -> ../init.d/ifupdown lrwxrwxrwx 1 root root 18 Oct 22 16:11 K07umountfs -> ../init.d/umountfs lrwxrwxrwx 1 root root 14 Oct 22 16:11 K08lvm2 -> ../init.d/lvm2 lrwxrwxrwx 1 root root 20 Oct 22 16:11 K09umountroot -> ../init.d/umountroot lrwxrwxrwx 1 root root 16 Oct 22 16:11 K10reboot -> ../init.d/reboot -rw-r--r-- 1 root root 351 Jan 1 2011 README }}} * [http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=466141 #466141 - lvm2: error message during shutdown (Can't deactivate volume group...) - Debian Bug report logs] > This is not a bug = LVM RAID = * [http://unix.stackexchange.com/questions/150644/raiding-with-lvm-vs-mdraid-pros-and-cons raid - RAIDing with LVM vs MDRAID - pros and cons? - Unix & Linux Stack Exchange] * Debian Wheezy/Jessie での例が詳しく載っている。LVM-RAIDについては情報が見つけにくいというのは現時点(2015/05)でもあまり変わらないように思える * LVM-RAIDは実体としてはMD-RAIDと同じらしい * [https://access.redhat.com/documentation/ja-JP/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/raid_volumes.html 4.4.15. RAID 論理ボリューム] * RHELでLVM-RAIDを使う際のマニュアル。「Red Hat Enterprise Linux 6.3 リリースでは、LVM は RAID4/5/6 およびミラーリングの新実装をサポートしています。」とある。 * [https://access.redhat.com/documentation/ja-JP/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/mirrorrecover.html 6.3. LVM ミラー障害からの回復] * このページの説明は、古い実装とされている[https://access.redhat.com/documentation/ja-JP/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/mirror_create.html 4.4.3. ミラー化ボリュームの作成]からリンクされているので、新実装で当てはまるのか不明 * なお、未翻訳のRHEL 7版でもほぼ同じ章立てになっている [https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Logical_Volume_Manager_Administration/ Logical Volume Manager Administration] * https://wiki.gentoo.org/wiki/LVM#Different_storage_allocation_methods > It is not possible to stripe an existing volume, nor reshape the stripes across more/less physical volumes, nor to convert to a different RAID level/linear volume. A stripe set can be mirrored. It is possible to extend a stripe set across additional physical volumes, but they must be added in multiples of the original stripe set (which will effectively linearly append a new stripe set). * RAID1,4,5,6でreshapeなどが使えないのは結構厳しい制限に思える。MD-RAIDでは可能なので、そのうちサポートされるかも知れない == LVM with MD-RAID == * [http://ruzia.hateblo.jp/entry/2014/01/04/203603 mdadm と LVM で作る、全手動 BeyondRAID もどき - 守破離] > ざっくり言うと、RAID1 か RAID5 でHDDを横断する領域をいくつか作って、その領域をまとめあげる事で大容量のストレージを作る感じですね。 > これのイケてる点は HDD が 1 台消えても大丈夫な上に、状況によっては HDD を 1 台交換するだけでストレージの容量がアップすること。 > 最低 2 台の HDD を大容量の物に交換すれば確実に容量が増えます。 = Thin provisioning = * https://www.kernel.org/doc/Documentation/device-mapper/thin-provisioning.txt > These targets are very much still in the EXPERIMENTAL state. Please do not yet rely on them in production. * https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Logical_Volume_Manager_Administration/LV.html#thinly_provisioned_volume_creation * https://wiki.gentoo.org/wiki/LVM#Thin_provisioning 非常に良くまとまっている * [http://lists.centos.org/pipermail/centos/2014-January/139850.html (CentOS) LVM thinpool snapshots broken in 6.5?] > For the people who run into this as well: > This is apparently a feature and not a bug. Thin provisioning snapshots > are no longer automatically activated and a "skip activation" flag is > set during creation by default. One has to add the "-K" option to > "lvchange -ay " to have lvchange ignore this flag and > activate the volume for real. "-k" can be used on lvcreate to not add > this flag to the volume. See man lvchange/lvcreate for more details. > /etc/lvm/lvm.conf also contains a "auto_set_activation_skip" option now > that controls this. > > Apparently this was changed in 6.5 but the changes were not mentioned in > the release notes. * thin snapshotはデフォルトではinactiveで作成され、activateするにはlvchangeに'-K'オプションが必要となった