OK hooray! Lustre setup with failover of all nodes, but now we have this huge lustre mount point. How can I say create /lustre/home and /lustre/groups and mount on the client? David -- Personally, I liked the university. They gave us money and facilities, we didn''t have to produce anything! You''ve never been out of college! You don''t know what it''s like out there! I''ve worked in the private sector. They expect results. -Ray Ghostbusters
David Noriega wrote:> OK hooray! Lustre setup with failover of all nodes, but now we have > this huge lustre mount point. How can I say create /lustre/home and > /lustre/groups and mount on the client? > > David >Two choices: 1) create two Lustre file systems (separate MDT and OSTs for each) 2) use "mount --bind" on the client to make one filesystem''s directories show up in different places
Ok, so I could do mount --bind /lustre/home /home mount --bind /lustre/groups /groups Is this a generally accepted practice with Lustre? This just seems so much like a nifty trick, but if its what the community uses, then ok. But ultimately if I wanted two separate filesystems, I would need more hardware? An OST can''t be put into a general ''pool'' for use between the two? David On Wed, Aug 18, 2010 at 12:33 PM, Kevin Van Maren <kevin.van.maren at oracle.com> wrote:> David Noriega wrote: >> >> OK hooray! Lustre setup with failover of all nodes, but now we have >> this huge lustre mount point. How can I say create /lustre/home and >> /lustre/groups and mount on the client? >> >> David >> > > Two choices: > > 1) create two Lustre file systems (separate MDT and OSTs for each) > 2) use "mount --bind" on the client to make one filesystem''s directories > show up in different places > >-- Personally, I liked the university. They gave us money and facilities, we didn''t have to produce anything! You''ve never been out of college! You don''t know what it''s like out there! I''ve worked in the private sector. They expect results. -Ray Ghostbusters
David Noriega wrote:> Ok, so I could do > mount --bind /lustre/home /home > mount --bind /lustre/groups /groups > > Is this a generally accepted practice with Lustre? This just seems so > much like a nifty trick, but if its what the community uses, then ok. >It is a pretty nifty trick. Same file system, so the same quotas (if any) would apply to both directories.> But ultimately if I wanted two separate filesystems, I would need more > hardware? An OST can''t be put into a general ''pool'' for use between > the two? >You probably don''t need more hardware, but you would have to decide which file system each OST would serve -- it can only provide space to one file system. So some of your OSTs would be for home and some for groups. You would need to have 2 MDTs (if necessary, you could split/partition the MDT you have). Kevin> David > > On Wed, Aug 18, 2010 at 12:33 PM, Kevin Van Maren > <kevin.van.maren at oracle.com> wrote: > >> David Noriega wrote: >> >>> OK hooray! Lustre setup with failover of all nodes, but now we have >>> this huge lustre mount point. How can I say create /lustre/home and >>> /lustre/groups and mount on the client? >>> >>> David >>> >>> >> Two choices: >> >> 1) create two Lustre file systems (separate MDT and OSTs for each) >> 2) use "mount --bind" on the client to make one filesystem''s directories >> show up in different places >> >> >> > > > >
On 2010-08-18, at 13:14, Kevin Van Maren wrote:> David Noriega wrote: >> But ultimately if I wanted two separate filesystems, I would need more >> hardware? An OST can''t be put into a general ''pool'' for use between >> the two? > > You probably don''t need more hardware, but you would have to decide > which file system each OST would serve -- it can only provide space to one file system. So some of your OSTs would be for home and some for groups. You would need to have 2 MDTs (if necessary, you could split/partition the MDT you have).To clarify, it is NOT possible to have an OST in more than one filesystem, but it IS possible to have multiple OSTs (RAID LUNs + ldiskfs filesystem) on the same OSS node exported to different Lustre filesystems. That said, this isn''t a very common configuration except in the smallest of installations, since you now have a single point of failure for BOTH filesystems, and there is little value in e.g. sharing /home and /groups both across the same 10 OSS nodes, instead of having 4 OSS nodes for /home and 6 separate OSS nodes for /groups (or whatever split is needed for your usage). For a small configuration it probably makes sense to share the space in a single filesystem as Kevin suggested. Cheers, Andreas -- Andreas Dilger Lustre Technical Lead Oracle Corporation Canada Inc.