[Lustre-discuss] Howto map block devices to Lustre devices?

Klaus Steden klaus.steden at thomson.net
Thu Mar 13 13:55:45 PDT 2008


Hi Chris,

Don't your Lustre volumes have a label on them?

On the one cluster I've got, the physical storage is shared with a number of
other systems, so the device information can change over time ... so I use
device labels in my /etc/fstab and friends.

Something like 'lustre-OST0000', 'lustre-OST00001' ... although when the
devices are actually mounted, they show up with their /dev node names.

Look through /proc/fs/lustre for Lustre volume names (they show up when
they're mounted), and you can winnow your list down by mounting by name,
checking the device ID, and removing it that way.

If you have a lot of devices on the same bus, it will likely take a bit for
the right one to be found, but it's there.

hth,
Klaus

On 3/13/08 12:50 PM, "Chris Worley" <worleys at gmail.com>did etch on stone
tablets:

> I'm trying to deactivate some OST's, but to find them I've been
> searching through /var/log/messages, as in:
> 
> # ssh io2 grep -e sde -e sdf -e sdj -e sdk -e sdd /var/log/messages"*"
> | grep Server
> /var/log/messages:Mar 10 13:27:54 io2 kernel: Lustre: Server
> ddnlfs-OST0035 on device /dev/sdf has started
> /var/log/messages.1:Mar  4 16:02:13 io2 kernel: Lustre: Server
> ddnlfs-OST0030 on device /dev/sdf has started
> /var/log/messages.1:Mar  6 14:34:44 io2 kernel: Lustre: Server
> ddnlfs-OST002e on device /dev/sdd has started
> /var/log/messages.1:Mar  6 14:34:55 io2 kernel: Lustre: Server
> ddnlfs-OST002f on device /dev/sde has started
> /var/log/messages.1:Mar  6 14:35:16 io2 kernel: Lustre: Server
> ddnlfs-OST0030 on device /dev/sdf has started
> /var/log/messages.1:Mar  6 15:20:48 io2 kernel: Lustre: Server
> ddnlfs-OST002f on device /dev/sde has started
> /var/log/messages.1:Mar  6 16:08:38 io2 kernel: Lustre: Server
> ddnlfs-OST002e on device /dev/sdd has started
> /var/log/messages.1:Mar  6 16:08:43 io2 kernel: Lustre: Server
> ddnlfs-OST0030 on device /dev/sdf has started
> /var/log/messages.1:Mar  6 16:08:53 io2 kernel: Lustre: Server
> ddnlfs-OST0034 on device /dev/sdj has started
> 
> Note that there isn't an entry for sdk (probably rotated out), and sdf
> has two different names.
> 
> Is there a better way to find the right Lustre device name map to
> Linux block device?
> 
> I'm trying to cull-out slow disks.  I'm hoping that just by
> "deactivating" the device in lctl, it'll quit using it, and that's the
> best way to get rid of a slow drive... correct?
> 
> Thanks,
> 
> Chris
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