Peter J. Braam
2006-Jun-18 11:18 UTC
[Lustre-discuss] Does Lustre Support Atomic O_APPEND and AtomicRename?
Hi Eser, Lustre does support concurrent O_APPENDS, and they will be atomic. There should be no danger of deadlocking. However, I think you will not find performance is so great - there will be a lot of lock ping-pong and cache flushes. (If time permits one day we may send O_APPEND directly to the server in case of concurrency.) Lustre rename is executed entirely on the server, atomically like for a local file system. The operations happen on different servers - the MDS for rename the OSS''s for appends. The file will be open so the rename isn''t really visible to the writers, they keep their file handle during the rename. - Peter -> -----Original Message----- > From: lustre-discuss-bounces@clusterfs.com > [mailto:lustre-discuss-bounces@clusterfs.com] On Behalf Of EKC > Sent: Wednesday, May 31, 2006 1:38 PM > To: lustre-discuss@clusterfs.com > Subject: [Lustre-discuss] Does Lustre Support Atomic O_APPEND > and AtomicRename? > > Hi, > > I have multiple lustre clients setup to do concurrent > O_APPEND writes to the same file. Each O_APPEND is on the > order of 1 megabyte. Does lustre guarantee atomic O_APPEND > operations? Also, is there a danger of deadlocking when I > have dozens of clients doing concurrent O_APPEND''s to the same file? > > I''d also like to be able to atomically rename this same file. > Does Lustre support an atomic file rename operation? I''m > assuming lustre will FIFO queue my rename and O_APPEND > operations on the same file, so my parent process will have > it''s O_APPEND or rename operation execue eventually. > > Thanks in advance, > > Eser > _______________________________________________ > Lustre-discuss mailing list > Lustre-discuss@clusterfs.com > https://mail.clusterfs.com/mailman/listinfo/lustre-discuss > >
EKC
2006-Jun-18 11:18 UTC
[Lustre-discuss] Does Lustre Support Atomic O_APPEND and Atomic Rename?
Hi, I have multiple lustre clients setup to do concurrent O_APPEND writes to the same file. Each O_APPEND is on the order of 1 megabyte. Does lustre guarantee atomic O_APPEND operations? Also, is there a danger of deadlocking when I have dozens of clients doing concurrent O_APPEND''s to the same file? I''d also like to be able to atomically rename this same file. Does Lustre support an atomic file rename operation? I''m assuming lustre will FIFO queue my rename and O_APPEND operations on the same file, so my parent process will have it''s O_APPEND or rename operation execue eventually. Thanks in advance, Eser