Linux RAID subsystem development
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* Expanding raid0
@ 2012-12-19 21:23 Kubes
  2012-12-21 17:32 ` Roy Sigurd Karlsbakk
  0 siblings, 1 reply; 4+ messages in thread
From: Kubes @ 2012-12-19 21:23 UTC (permalink / raw)
  To: linux-raid

All,

I have yet to find THE definitive word (via any search and forums) if
this is possible;  expanding a raid0 set by adding drives.  (Please, I
know there is no redundancy, and that is fine as these volumes are
really Amazon WS EBS volumes, so we only strip for speed improvements)



It seem this works:
  more /proc/diskstats
  mdadm --create /dev/md0 --chunk=256 --level=0 --raid-devices=2 /dev/sd[b-c]
  mdadm --detail /dev/md0
  mkfs.xfs /dev/md0
  mount /dev/md0 /mnt
  vi /mnt/test
  umount /dev/md0

  mdadm --grow /dev/md0 --level=0 --backup-file=/tmp/grow
--raid-devices=3 --add /dev/sdd   <= changes to raid4
  mdadm --detail /dev/md0
  mdadm --grow /dev/md0 --level=0 --backup-file=/tmp/grow  <== changes to raid0
  mdadm --detail /dev/md0

Can someone please confirm this correct and that raid0 can be
expanded, or is there a better means to expand an raid0 raid set?

Thanks!

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Expanding RAID0
@ 2015-09-02  8:57 Alexander Afonyashin
  2015-09-03 10:53 ` Alexander Afonyashin
  0 siblings, 1 reply; 4+ messages in thread
From: Alexander Afonyashin @ 2015-09-02  8:57 UTC (permalink / raw)
  To: linux-raid

Hi,

I added 3rd drive to 2-disk raid0 (with some issues like mdadm hung
and all disks became spares) but now it looks like:

md3 : active raid4 sda4[0] sdc4[3] sdb4[1]
      1304305152 blocks super 1.2 level 4, 512k chunk, algorithm 5 [4/3] [UUU_]

(/dev/sdc4 was added). I wonder what should be better to convert raid4
back to raid0 again:
- mdadm -G -l 0 -n 0 /dev/md3
or
- echo 0 > /sys/block/md3/md/level

Which command doesn't start 'sync' process again? (I suspect that
first one does)

Regards,
Alexander Afonyashin

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2015-09-03 10:53 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-12-19 21:23 Expanding raid0 Kubes
2012-12-21 17:32 ` Roy Sigurd Karlsbakk
  -- strict thread matches above, loose matches on Subject: below --
2015-09-02  8:57 Expanding RAID0 Alexander Afonyashin
2015-09-03 10:53 ` Alexander Afonyashin

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