Re: [Lustre-discuss] MGS disk size and activity
Hi, I am very interested in finding out how to move co-located MGS to separate disk. I will be moving my MDTs to new hardware soon and I would like to separate MGS from MDT. I will be grateful for some info on this subject please. Many thanks, Wojciech 2008/6/23 Andreas Dilger adil...@sun.com On Jun 17, 2008 12:40 -0700, Klaus Steden wrote: I have a question ... if the MGS is used so infrequently relative to the use of the MDS, why is it (is it?) problematic to locate it on the same volume as the MDT? If you have multiple MDTs on the same MDS node (i.e. multiple Lustre filesystems) then it is difficult to start up the MGS separately from the MDT if it is co-located with one of the MDTs. It isn't impossible (with some manual mounting of the underlying filesystems) to move a co-located MGS to a separate filesystem if needed. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss -- -- Wojciech Turek Assistant System Manager High Performance Computing Service University of Cambridge Email: wj...@cam.ac.uk Tel: (+)44 1223 763517 ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
Re: [Lustre-discuss] MGS disk size and activity
On Jun 17, 2008 12:40 -0700, Klaus Steden wrote: I have a question ... if the MGS is used so infrequently relative to the use of the MDS, why is it (is it?) problematic to locate it on the same volume as the MDT? If you have multiple MDTs on the same MDS node (i.e. multiple Lustre filesystems) then it is difficult to start up the MGS separately from the MDT if it is co-located with one of the MDTs. It isn't impossible (with some manual mounting of the underlying filesystems) to move a co-located MGS to a separate filesystem if needed. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
Re: [Lustre-discuss] MGS disk size and activity
On Tue, 2008-06-17 at 11:09 -0400, Brock Palen wrote: A post a few days back recommended that the MGS be placed on its own disk for all but toy setups I think was the comment. Yeah. How much space does the MGS require? Very little. I think we have discussed here that 100MB should be lots for now and the future. Perhaps somebody who knows more about what changes could be happening to configuration logs might know better. Is it based on the number of hosts? Or just the number of lustre file systems (we expect only 1 but maybe more in future). Well, it would be both, but the amount of data per host (where a host is an OSS, MDS) is relatively small. Last what's the IO requirements of the MGS? Again, small. It's used when a new OST or MDT is added to record their addition and when nodes join the filesystem or when a configuration change with a --writeconf is done. I don't think it would be much, such that could it share spindles with the journal for the MDS file system? Hrm. Given it's relatively low use, I'd think that would be fine. b. signature.asc Description: This is a digitally signed message part ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
Re: [Lustre-discuss] MGS disk size and activity
I don't think it would be much, such that could it share spindles with the journal for the MDS file system? Hrm. Given it's relatively low use, I'd think that would be fine. I have a question ... if the MGS is used so infrequently relative to the use of the MDS, why is it (is it?) problematic to locate it on the same volume as the MDT? thanks, Klaus ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
Re: [Lustre-discuss] MGS disk size and activity
On Tue, 2008-06-17 at 12:40 -0700, Klaus Steden wrote: I have a question ... if the MGS is used so infrequently relative to the use of the MDS, why is it (is it?) problematic to locate it on the same volume as the MDT? Our mountconf expert engineers probably know all of the reasons but one is that if you have multiple filesystems and you need to reformat the MDT that is shared with the MGS for some reason, you end up losing configuration logs for all of your filesystems. b. signature.asc Description: This is a digitally signed message part ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
