On Wed, Jan 26, 2011 at 10:53:17PM -0500, Mark Lord wrote: > On 11-01-26 10:43 PM, Dave Chinner wrote: > > On Wed, Jan 26, 2011 at 08:43:43PM -0500, Mark Lord wrote: > >> On 11-01-26 08:22 PM, Mark Lord wrote: > .. > >> Thinking about it some more: the first problem very much appears as if > >> it is due to a filesystem check happening on the already-mounted filesystem, > >> if that makes any kind of sense (?). > > > > Not to me. You can check this simply by looking at the output of > > top while the problem is occurring... > > Top doesn't show anything interesting, since disk I/O uses practically zero CPU. My point is that xfs_check doesn't use zero cpu or memory - it uses quite a lot of both, so if it is not present in top output while the disk is being thrashed, it ain't running... > > >> running xfs_check on the umounted drive takes about the same 30-60 seconds, > >> with the disk activity light fully "on". > > > > Well, yeah - XFS check reads all the metadata in the filesystem, so > > of course it's going to thrash your disk when it is run. The fact it > > takes the same length of time as whatever problem you are having is > > likely to be coincidental. > > I find it interesting that the mount takes zero-time, > as if it never actually reads much from the filesystem. > Something has to eventually read the metadata etc. Sure, for a clean log it has basically nothing to do - a few disk reads to read the superblock, find the head/tail of the log, and little else needs doing. Only when log recovery needs to be done does mount do any significant IO. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
