[Lustre-discuss] unable to mount ost

[Daire Byrne]

Rayentray,

----- "Rayentray Tappa" <rtappa.ascentio at gmail.com> wrote:

> I created an OST today by running:
> mkfs.lustre --fsname=testfs --ost --mgsnode=192.168.6.199 at tcp /dev/sda3
> 
> (ltcl list_nids in the mdt/mgs gave me the 192.168.6.199 at tcp hint)

Looks reasonable.

> When I want to mount it, I get:
>  mount -t lustre /dev/sda3 /mnt/test/ost0/mount.lustre: mount
> /dev/sda3
> at /mnt/test/ost0 failed: Input/output error
> Is the MGS running?
> 
> So I wonder: is there anything else I should tell the MGS to do
> besides mounting it? (It *is* mounted and running)

Assuming you did something like this on 192.168.6.199 first:

  mkfs.lustre --fsname testfs --mdt --mgs /dev/sda
  mount -t lustre /dev/sda /mnt/mdt

that should be all that you need to do. You may need to check your lustre
networking and make sure that lnet has bound to the correct network device
(i.e. eth0) and that the IPs match. You can usually check this in dmesg.

You may need this in your modprobe.conf:

  options lnet networks=tcp

> Also: I want to create another OST in the same server as the previous
> one. How can i distinguish each (besides knowing which device they're
> using). Is the --fsname option to be used for that purpose? I first
> understood the fsname should be the same for all the mdt/ost but now
> I think it again maybe it should be different for everyone?

To create another OST you just give another device name to mkfs.lustre and 
mount. Once they make contact with the MGS for the first time the device label
is updated so that:

  # e2label /dev/lustre/ost1
  epsilon-OST0000
  # e2label /dev/lustre/ost2
  epsilon-OST0001

You can then mount by label in your fstab if you want. The "OST00xx" index is
generated by first mount order (not format order).

Daire