On Jan 27, 2011, at 3:15 AM, Andreas Dilger wrote: > On 2011-01-25, at 17:05, Jeremy Filizetti wrote: >> On Fri, Jan 21, 2011 at 1:02 PM, Andreas Dilger <[email protected]> >> wrote: >>> 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. >>> >> >> We use Lustre in a WAN environment and each geographic location has their >> own Lustre file system with it's own MGS. While I don't add storage >> frequently I've never seen an issue with this. >> >> Just to be sure I just mounted a test file system, follewed by another file >> system and added an OST to the test file system and the client was notified >> by the MGS. Looking at "lctl dl" the client shows a device for MGC and I >> see connections in the peers list. I didn't test any conf_param, but at >> least the connections look fine including the output from the "lctl dk". >> >> Is there something I'm missing here? I know each OSS shares a single MGC >> between all the OBDs so that you can really only mount one file system at a >> time in Lustre. Is that what you are referring to? > > Depending on how you ran the test, it is entirely possible that the client > hadn't been evicted from the first MGS yet, and it accepted the message from > this MGS even though this was evicted. However, if you check the connection > state > on the client (e.g. "lctl get_param mgc.*.import") it is only possible for > the client to have a single MGC today, and that MGC can only have a connection > to a single MGS at a time. > > Granted, it is possible that someone fixed this when I wasn't paying > attention.
I thought this sounded familiar - have a look at bz 20299. Multiple MGCs on a client are ok; multiple MGSes on a single server are not. Jason -- Jason Rappleye System Administrator NASA Advanced Supercomputing Division NASA Ames Research Center Moffett Field, CA 94035 _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
