On 4 February 2013 20:29, Mathias Burén [off-list ref] wrote:

On 4 February 2013 20:27, Mathias Burén [off-list ref] wrote:

quoted

Hi list,

I've an Intel Atom 330 running 32-bit Ubuntu, ~3.5GB RAM. The intent
is to store large media files (>4GB) for streaming by maximum 3
clients at any time. Very read heavy.
6x 2TB HDDs are available, the crux is that 3 HDDs are on the on-board
SATA controller, the other 3 are on a Marvel PCI-E adapter

I was clearly not thinking when doing this. Now it's a 6 disk RAID10
with far layout, 2 copies. Is the default chunk size of 512 a good
option here?

$ sudo mdadm --verbose --create md0 --level=10 --layout=f2
--raid-devices=6 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg
mdadm: chunk size defaults to 512K
mdadm: size set to 1953382912K
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md/md0 started.


$ cat /proc/mdstat
Personalities : [raid10] [raid0]
md127 : active raid10 sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0]
      5860147200 blocks super 1.2 512K chunks 2 far-copies [6/6] [UUUUUU]
      [>....................]  resync =  0.0% (775616/5860147200)
finish=629.5min speed=155123K/sec

unused devices: <none>
@ion:~$ sudo mdadm -D /dev/md/md0
/dev/md/md0:
        Version : 1.2
  Creation Time : Mon Feb  4 20:40:22 2013
     Raid Level : raid10
     Array Size : 5860147200 (5588.67 GiB 6000.79 GB)
  Used Dev Size : 1953382400 (1862.89 GiB 2000.26 GB)
   Raid Devices : 6
  Total Devices : 6
    Persistence : Superblock is persistent

    Update Time : Mon Feb  4 20:40:22 2013
          State : clean, resyncing
 Active Devices : 6
Working Devices : 6
 Failed Devices : 0
  Spare Devices : 0

         Layout : far=2
     Chunk Size : 512K

  Resync Status : 0% complete

           Name : ion:md0  (local to host ion)
           UUID : 438e9a1a:bf840b03:05c36383:c965cb39
         Events : 0

    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
       3       8       64        3      active sync   /dev/sde
       4       8       80        4      active sync   /dev/sdf
       5       8       96        5      active sync   /dev/sdg

Kind regards,
Mathias
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