On 01/21/2011 07:02 PM, Andreas Dilger wrote: > On 2011-01-21, at 06:55, Ben Evans wrote: >> In our lab, we've never had a problem with simply having 1 MGS per >> filesystem. Mountpoints will be unique for all of them, but functionally it > works just fine. > > While this "runs", it is definitely not correct. The problem is that the > client will only connect to a single MGS for configuration updates (in > particular, the MGS for the last filesystem that was mounted). If there is a > configuration change (e.g. lctl conf_param, or adding a new OST) on one > of the other filesystems, then the client will not be notified of this change > because it is no longer connected to the MGS for that filesystem. > > I agree that it would be desirable to allow the client to connect to multiple > MGSes, but it doesn't work today. I'd be thrilled if some interested > party were to fix that. >
Ah, thanks Andreas, that would be a point we'd miss with test clusters. I had only seen this effect when deactivating OST using the device number instead of the name, and a client with multiple MGSes could have a different numbering. Very well, we'll stick to one MGS, then. Thomas >> -----Original Message----- >> From: [email protected] on behalf of Thomas Roth >> Sent: Fri 1/21/2011 6:43 AM >> To: [email protected] >> Subject: [Lustre-discuss] MDT raid parameters, multiple MGSes >> >> Hi all, >> >> we have gotten new MDS hardware, and I've got two questions: >> >> What are the recommendations for the RAID configuration and formatting >> options? >> I was following the recent discussion about these aspects on an OST: >> chunk size, strip size, stride-size, stripe-width etc. in the light of >> the 1MB chunks of Lustre ... So what about the MDT? I will have a RAID >> 10 that consists of 11 RAID-1 pairs striped over. giving me roughly 3TB >> of space. What would be the correct value for <insert your favorite >> term>, the amount of data written to one disk before proceeding to the >> next disk? >> >> Secondly, it is not yet decided whether we wouldn't use this hardware to >> set up a second Lustre cluster. The manual recommends to have only one >> MGS per site, but doesn't elaborate: what would be the drawback of >> having two MGSes, two different network addresses the clients have to >> connect to to mount the Lustres? >> I know that it didn't work in Lustre 1.6.3 ;-) and there are no apparent >> issues when connecting a Lustre client to a test cluster now (version >> 1.8.4), but what about production? >> >> >> Cheers, >> Thomas >> _______________________________________________ >> Lustre-discuss mailing list >> [email protected] >> http://lists.lustre.org/mailman/listinfo/lustre-discuss >> >> >> _______________________________________________ >> Lustre-discuss mailing list >> [email protected] >> http://lists.lustre.org/mailman/listinfo/lustre-discuss > > > Cheers, Andreas > -- > Andreas Dilger > Principal Engineer > Whamcloud, Inc. > > > -- -------------------------------------------------------------------- Thomas Roth Department: Informationstechnologie Location: SB3 1.262 Phone: +49-6159-71 1453 Fax: +49-6159-71 2986 GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 1 64291 Darmstadt www.gsi.de Gesellschaft mit beschränkter Haftung Sitz der Gesellschaft: Darmstadt Handelsregister: Amtsgericht Darmstadt, HRB 1528 Geschäftsführung: Professor Dr. Dr. h.c. Horst Stöcker, Dr. Hartmut Eickhoff Vorsitzende des Aufsichtsrates: Dr. Beatrix Vierkorn-Rudolph Stellvertreter: Ministerialdirigent Dr. Rolf Bernhardt _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
