On 23 November 2010 19:49, Kurt Lidl <[email protected]> wrote: > On Tue, Nov 23, 2010 at 10:38:31AM -0800, Chris St Denis wrote: > > Is this just due to the very high io bandwidth usage associated with > > making a snapshot, or does the creation of this snapshot completely > > block IO writes for around 5 minutes? > > It blocks updates to the filesystem while during part of the > snapshot process. > > See the comments in /usr/src/sys/ufs/ffs/ffs_snapshot.c > > I found using UFS snapshots on a production fileserver untenable > during normal working hours. I have a backup fileserver that I > rsync the files to, and then use the UFS snapshots there. > > > Any suggested workarounds? I already bumped up the number of Apache > > slots to 166% but it looks like I would have to increase the number much > > more to use that as a primary solution. > > Use ZFS. The way snapshots work there, they are nearly instantanous > to create, and you are not limited to 20 snapshots per filesystem. > > -Kurt > _______________________________________________ > [email protected] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "[email protected]" >
I can testify zfs snapshots are very usable, as we use it to backup our mysql and oracle databases. Issue a write lock, flush, snap, remove lock, backup snapshot All takes a few seconds and is fairly seamless _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[email protected]"
