[Lustre-discuss] Migrating MDT volume to a new location

[Thomas Roth]

On 02.02.2011 18:15, Bob Ball wrote:
> Is there a recommended way to migrate an MDT (MGS is separate) volume
> from one location to another on the same server?  This uses iSCSI volumes.
>
> Lustre 1.8.4
>

We'll try the copy (DRBD) + resize variant soon. I've tried that with a 
backup copy of the MDT up to the stage where I had mounted the MDT disk 
and then would need a network connection to the MGS - with the 
production system running, I couldn't test that.

Copying via tar never succeeded in our system - I think because of 
limits in tar.
But I tried to copy via rsync: takes weeks! Neither the amount of bytes 
to be transfered (45 GB) nor the network bandwidth (10 Gb) is an issues, 
but we have 110 mio inodes in use, so rsync probably takes its time to 
go through all these (sparse) files. Consequently, there can be no 
lengthy first copy from a backup and a quick final sync while Lustre has 
been taken down - that step would last just as long.

Regards,
Thomas