Thanks both for your replies. In the mean time we've upgraded our file system to 1.8.3-ddn3.3, which kept us busy, so sorry for the late reply. In our initial testing we've not seen this problem but more testing is in progress.
Andreas Dilger wrote: > On 2010-10-29, at 21:20, Daniel Kobras wrote: >> On Fri, Oct 29, 2010 at 09:40:33AM +0100, Frederik Ferner wrote: >>> Doing a 'strace -T -e file ls -n' on one directory with about 750 >>> files, while users were seeing the hanging ls, showed lstat calls >>> taking seconds, up to 23s. >> The (l)stat() calls determine the exact size of all files in the >> displayed directory. This means that each OSTs needs to revoke >> client write locks for all these files, ie. client-side write >> caches for all files in the directory are flushed before the >> (l)stat() returns. This can easily take several seconds if there is >> heavy write activity on the file. As far as I was able to see at that time, the actual files were not written to anymore but additional files in the directory or one directory below were still created. > Actually, unlike most other cluster filesystems Lustre does not need > to revoke the OST write locks in order to determine the file size. > The OST extent locks are conditionally revoked if the client is no > longer using them, but if they are in use the clients holding those > locks only return a "glimpse" of the current file size to the OST, > which in turn returns the size to the client doing the (l)stat() > call. I assume on a busy OST this could still take a while, though? We'll monitor the situation after the upgrade and if it happens again, we'll try more debugging again. Thanks, Frederik -- Frederik Ferner Computer Systems Administrator phone: +44 1235 77 8624 Diamond Light Source Ltd. mob: +44 7917 08 5110 (Apologies in advance for the lines below. Some bits are a legal requirement and I have no control over them.) _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
