Setup 1x RAID5 array with multiple LVs and differnt filesystems?

Question

Centos 5.9 - 2.6.18-348.3.1.el5 i686

Raid5 - 4 Disks + 1 Spare (all WD RED 3TB)

Does it make sence to create multiple LV within the same VP and configure them as differnt filesystems:

Example:
LV1: ext4 - photo backup - so lots of smaller files
LV2: xfs  - server backups - so lots of large-to-massive files
LV3: ext4 - other data backups - mixture of small-to-medium sized files

I created the RAID in the following way:

mdadm --create --verbose /dev/md0 --metadata=1.2 --chunk=128 --level=5 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde --spare-devices=1 /dev/sdf

I created the filesyatems in the following way:

mkfs -t ext4 -E stride=32 -m 0 -O extents,uninit_bg,dir_index,filetype,has_journal,sparse_super /dev/RaidVolGroup00/RaidPhotoBkpVo

mkfs.xfs -d sunit=256,swidth=768 /dev/RaidVolGroup00/RaidServerBkpVo

mkfs -t ext4 -E stride=32 -m 0 -O extents,uninit_bg,dir_index,filetype,has_journal,sparse_super /dev/RaidVolGroup00/RaidDataBkpVo

Here a bit about my config: ???anybody an idea why/is that normal that "metadata format 1.02 unknown" is showing below in the details of md0???

mdadm --detail /dev/md0

mdadm: metadata format 1.02 unknown, ignored.
/dev/md0:
        Version : 01.02.03
  Creation Time : Thu Apr  4 17:07:55 2013
     Raid Level : raid5
     Array Size : 8790799104 (8383.56 GiB 9001.78 GB)
  Used Dev Size : 5860532736
   Raid Devices : 4
  Total Devices : 5
Preferred Minor : 0
    Persistence : Superblock is persistent

Update Time : Thu Apr  4 19:33:36 2013
      State : clean, degraded, recovering
 Active Devices : 3
Working Devices : 5
 Failed Devices : 0
  Spare Devices : 2

     Layout : left-symmetric
 Chunk Size : 128K

 Rebuild Status : 39% complete

       Name : 0
       UUID : 05b9571d:c0383b8a:7459a33d:394b4c56
     Events : 106

Number   Major   Minor   RaidDevice State
   0       8       16        0      active sync   /dev/sdb
   1       8       32        1      active sync   /dev/sdc
   2       8       48        2      active sync   /dev/sdd
   5       8       64        3      spare rebuilding   /dev/sde

   4       8       80        -      spare   /dev/sdf

lvdisplay RaidVolGroup00

  --- Logical volume ---
  LV Name                /dev/RaidVolGroup00/RaidPhotoBkpVo
  VG Name                RaidVolGroup00
  LV UUID                jEeXx1-0By2-Vtn3-kC08-AP2n-l9xh-xJhl9F
  LV Write Access        read/write
  LV Status              available
  # open                 0
  LV Size                1006.02 GB
  Current LE             257542
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     1536
  Block device           253:0

  --- Logical volume ---
  LV Name                /dev/RaidVolGroup00/RaidServerBkpVo
  VG Name                RaidVolGroup00
  LV UUID                iZ3Cwu-yoNo-3Gqn-Xwpx-Q0xT-3Kws-KUzNjy
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                3.24 TB
  Current LE             849892
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     1536
  Block device           253:1

  --- Logical volume ---
  LV Name                /dev/RaidVolGroup00/RaidDataBkpVo
  VG Name                RaidVolGroup00
  LV UUID                90uQ0H-Exz0-qJ8I-IXGq-1l8Z-srVx-1GvpNT
  LV Write Access        read/write
  LV Status              available
  # open                 0
  LV Size                2.97 TB
  Current LE             779067
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     1536
  Block device           253:2

Still have 1 TB unused disk space in case I need to "grow" any of the partitions but I have plans, in near future, expanding to more disks per SATA channel/port via a 1 to 5 - sil3726 based - SATA Port Multiplier, which can do command based and !!FIS–based switching! so my LV will increae!

Hope that is enougth info for now and that some can pls advice Tnx a mill Regards Andre

score 0 · Answer 1 · answered Aug 06 '13 at 15:30

Yes, it is reasonable to create multiple LVs as different mountpoints (as well as multiple filesystems types, if for some partition you prefer features of some other like XFS).

The warning is there because your forced version of metadata with "mdadm ... --metadata=1.2" (why did you do that? there is no need to specify it - mdadm will choose best one!) which your version of mdadm does not seem to support (it seems strange that you managed to specify it - which version of mdadm is it?)

Looking through mdadm 3.1.4 and its source it should not be possible to specify invalid format or one that is misunderstood, but "mdadm: metadata format 1.02 unknown, ignored." seems harmless enough, as it is only used (apart from creation phase which seems to be working for you) for displaying information. You may want to reformat again (doing backup/restore if you have needed data on that disks) if you want to get rid of it though, as it might confuse future versions of mdadm and cause breakage.

Setup 1x RAID5 array with multiple LVs and differnt filesystems?

1 Answers1