wiki:TipAndDoc/storage/LVM

Version 16 (modified by mitty, 10 years ago) (diff)

--

  1. lvchange/vgchange -ay
  2. Can't deactivate
  3. LVM RAID
    1. LVM with MD-RAID
  4. Thin provisioning
    1. metadata
    2. /etc/lvm/lvm.conf
      1. error_when_full

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"
  • 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!
  • 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

LVM RAID

  • ​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

  • ​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

  • ​(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 <snapshot-volume>" 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('-k y -K'とするのが良さそう)

metadata

/etc/lvm/lvm.conf

error_when_full

  • 0 (default)
    • thin poolが一杯になると、書き込みはキューイングされる。thin poolはout-of-data-space modeになる 
      May 10 12:35:10 raid-test lvm[303]: Thin vg-pool0-tpool is now 96% full.
May 10 12:40:36 raid-test kernel: device-mapper: thin: 252:2: reached low water mark for data device: sending event.
May 10 12:40:36 raid-test kernel: device-mapper: thin: 252:2: switching pool to out-of-data-space mode
May 10 12:40:36 raid-test lvm[303]: Thin vg-pool0-tpool is now 100% full.
    • #l vs -a -o+lv_when_full 
        LV              VG   Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert WhenFull
  lv1             vg   Vwi-aotz--   3.00g pool0        66.67
  pool0           vg   twi-aotzD-   2.00g              100.00 25.98                            queue
    • (デフォルトでは)60秒、thin poolが拡張されるのを待ち、失敗するとファイルシステムへエラーを返す。thin poolは read-only modeになる 
      May 10 12:41:36 raid-test kernel: device-mapper: thin: 252:2: switching pool to read-only mode
May 10 12:41:36 raid-test kernel: EXT4-fs warning (device dm-8): ext4_end_bio:317: I/O error -5 writing to inode 17 (offset 25165824 size 8388608 starting block 591856)
May 10 12:41:36 raid-test kernel: buffer_io_error: 38109 callbacks suppressed
May 10 12:41:36 raid-test kernel: Buffer I/O error on device dm-8, logical block 591856
May 10 12:41:36 raid-test kernel: EXT4-fs warning (device dm-8): ext4_end_bio:317: I/O error -5 writing to inode 17 (offset 25165824 size 8388608 starting block 591857)
May 10 12:41:36 raid-test kernel: Buffer I/O error on device dm-8, logical block 591857

(snip)

May 10 12:41:36 raid-test kernel: device-mapper: thin: 252:2: metadata operation 'dm_pool_commit_metadata' failed: error = -1
May 10 12:41:36 raid-test kernel: device-mapper: thin: 252:2: aborting current metadata transaction
May 10 12:41:36 raid-test kernel: device-mapper: thin: 252:2: switching pool to read-only mode
    • # lvs -a -o+lv_when_full 
        LV              VG   Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert WhenFull
  lv1             vg   Vwi-aotz--   3.00g pool0        66.67
  pool0           vg   twi-aotzM-   2.00g              100.00 25.98                            queue
    • read-onlyから復旧するには、全てのthin LVをinactivate -> thin pool LVをinactivate -> lvconvert --repair thinpoolLV する必要がある
  • 1
    • thin poolが一杯になると、書き込みは即座に失敗する。 
      May 10 12:53:17 raid-test kernel: device-mapper: thin: 252:2: reached low water mark for data device: sending event.
May 10 12:53:17 raid-test kernel: device-mapper: thin: 252:2: switching pool to out-of-data-space mode
May 10 12:53:17 raid-test kernel: EXT4-fs warning (device dm-8): ext4_end_bio:317: I/O error -28 writing to inode 17 (offset 33554432 size 8388608 starting block 591872)
May 10 12:53:17 raid-test kernel: buffer_io_error: 39292 callbacks suppressed
May 10 12:53:17 raid-test kernel: Buffer I/O error on device dm-8, logical block 591872
May 10 12:53:17 raid-test kernel: EXT4-fs warning (device dm-8): ext4_end_bio:317: I/O error -28 writing to inode 17 (offset 33554432 size 8388608 starting block 591873)

(snip)

May 10 12:53:17 raid-test lvm[303]: Thin vg-pool0-tpool is now 100% full.
May 10 12:53:27 raid-test kernel: EXT4-fs warning: 135366 callbacks suppressed
May 10 12:53:27 raid-test kernel: EXT4-fs warning (device dm-8): ext4_end_bio:317: I/O error -28 writing to inode 17 (offset 588054528 size 4857856 starting block 727248)
May 10 12:53:27 raid-test kernel: buffer_io_error: 135366 callbacks suppressed

(snip)
    • # lvs -a -o+lv_when_full 
        lv1             vg   Vwi-aotz--   3.00g pool0        66.67
  pool0           vg   twi-aotzD-   2.00g              100.00 26.86                            error
    • fstrimなどを用いて、割り当てを解放すると、すぐに復旧する 
      May 10 12:55:29 raid-test kernel: device-mapper: thin: 252:2: switching pool to write mode
May 10 12:55:29 raid-test kernel: device-mapper: thin: 252:2: switching pool to write mode
    • # lvs -a -o+lv_when_full 
        lv1             vg   Vwi-aotz--   3.00g pool0        65.62
  pool0           vg   twi-aotz--   2.00g              98.44  26.46                            error
  • オンラインで即座に変更可能
    • # lvchange --errorwhenfull y vg/pool0 
        Logical volume "pool0" changed.

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