I think the exception may be when doing a recursive snapshot - ZFS appears to halt IO so that it can take all the snapshots at the same instant.
At least, that's what it looked like to me. I've got an Opensolaris ZFS box providing NFS to VMWare, and I was getting SCSI timeout's within the Virtual Machines that appeared to happen exactly as the snapshots were taken. When I turned off the recursive snapshots, and rather had each FS snapshot individually, the problem went away. Regards, Tristan. -----Original Message----- From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-boun...@opensolaris.org] On Behalf Of Richard Elling Sent: Saturday, 14 November 2009 5:02 AM To: Rodrigo E. De León Plicet Cc: zfs-discuss@opensolaris.org Subject: Re: [zfs-discuss] Snapshot question On Nov 13, 2009, at 6:43 AM, Rodrigo E. De León Plicet wrote: > While reading about NILFS here: > > http://www.linux-mag.com/cache/7345/1.html > > > I saw this: > > One of the most noticeable features of NILFS is that it can > "continuously and automatically save instantaneous states of the > file system without interrupting service". NILFS refers to these as > checkpoints. In contrast, other file systems such as ZFS, can > provide snapshots but they have to suspend operation to perform the > snapshot operation. NILFS doesn't have to do this. The snapshots > (checkpoints) are part of the file system design itself. > > I don't think that's correct. Can someone clarify? It sounds to me like they confused Solaris UFS with ZFS. What they say applies to UFS, but not ZFS. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss