Rafa Griman wrote: > Hi all :) > > Got a customer (It is quite bad form to ask for help for a commercial deal without using your work email address. I assume you still work for Bull?)
> with: > - 1 x S2A9900 (one couplet) > - 500 x 2 TB drives > - 4 OSS > > This customer wants to add: > - 1 x S2A9900 (one couplet) > - 300 x 2 TB drives > - 4 OSS > > I know we could "just add" and restripe the existing files. But the > customer wants to physically move 100 drives from the existing S2A9900 > to the new one in order to have 400 drives on one S2A9900 and 400 > drives on the other one. > > So my questions are: > 1.- Can this be done (move drives between OSTs) without losing data? > First, make sure DDN supports moving drives _data intact_. The drives in each tier will at least have to end up as an ordered tier for this to work, but I would guess it isn't quite so simple. > 2.- Can an OST be moved from one OSS to another without losing data? > Yes, IF it is done properly. Step 1, back up all essential data. Step 2, add the _new server_ as a failover node for the OSTs being moved. Note that this requires a "tunefs.lustre --writeconf" (with new parameters on the OSTs being moved) and re-mounting all the servers. Step 3, move the drives Step 4, update the server/failover NIDs, removing the old ones with another writeconf pass. I _strongly_ recommend that you verify their Lustre support contract is current, and that you do a dry-run in a test environment before doing it live (if nothing else, you do have 4 servers and a new couplet to play with). > 3.- Has anyone done this? How? > > I imagine it can be done restriping files/migrating files within the > Lustre filesystem, removing "empty" OSTs, ... > Well, yes, there is that option as well; use lfs_migrate (at least 2 passes). > TIA > > Rafa > Kevin _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
