it is time for me to move my MDS to a diferent HW infrastructure.
So I Was wondering if the following procedure can work.
I have mds1 (old mds) and mds2 (new mds). On the old mds I have a zfs
MGS partition and a zfs MDT partition.
* create a new ZFS MGS and MDT partition on mds2 and create a lustre
FS on it
* umount lustre on mds2
* stop all the OSSes belonging to mds1 and stop and umount lustre on mds1
* zfs send the MGS partition from mds1 and zfs receive it on mds2
* zfs send the MGT partition from mds1 and zfs receive it on mds2
* mount lustre on mds2
should it work ?
thanks
Rick
On 8/23/18 2:40 PM, Mohr Jr, Richard Frank (Rick Mohr) wrote:
On Aug 22, 2018, at 8:10 PM, Riccardo Veraldi <riccardo.vera...@cnaf.infn.it>
wrote:
On 8/22/18 3:13 PM, Mohr Jr, Richard Frank (Rick Mohr) wrote:
On Aug 22, 2018, at 3:31 PM, Riccardo Veraldi <riccardo.vera...@cnaf.infn.it>
wrote:
I would like to migrate this virtual machine to another infrastructure. it is
not simple because the other infrastructure is vmware.
what is the best way to migrate those partitions without incurring into any
corruption of data ?
May I simply use zfs send and zfs receive thru SSH ?
what is the best way to move a MDS based virtual machine ?
I don’t have much experience with VMs, but I have used zfs send/receive to
migrate a MDT from one server to another. It worked quite well.
that's encouraging. it should work for VM too then regardless.
I have many MDSes as virtual machines. I found it to be a good way for high
availability, they perform well enough.
so what you do is to shut down lustre on OSSes and MDS. At this point you
simply zfs send and zfs receive on the new MDS ?
once the operation is terminated the new MDS is just ready to be used ?
It is possible to take snapshots on the current MDT and do incremental
send/receives to the new MDT while the system is still up and running. When
you are ready to switch over, then you shutdown the file system, do a final
send/receive, and then start the new MDS. The new MDS will need to have the
same configuration (NID, etc.) as the old MDS (unless you want to perform a
writeconf).
There was a talk at LUG in 2017 from someone who did something similar with
OSTs:
http://cdn.opensfs.org/wp-content/uploads/2017/06/Wed06-CroweTom-lug17-ost_data_migration_using_ZFS.pdf
That should give you a good idea of how to proceed.
--
Rick Mohr
Senior HPC System Administrator
National Institute for Computational Sciences
http://www.nics.tennessee.edu
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