You are not able to create a new snapshot in a RO VSM destination via snapmirror, that’s why it simply chooses the most recent one. In a QSM, the volume itself is RW, so you can. I have clients that have been backing up snapmirror destinations for years with no issue.
-Glenn
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Kennedy, Jeffrey Sent: Tuesday, November 23, 2010 2:54 PM To: Fred Grieco; Jeremy Webber Cc: toasters@mathworks.com Subject: RE: NDMP backup of snapmirror target
If I’m understanding you and Ed correctly though, the backup software in both cases used an existing snapshot, it did not make a snapshot itself?
At some point in the past Netbackup, Bodtool, Commvault, etc., would all create their own backup_stuff.0 snapshot what was specifically for NDMP backups and was (supposedly) deleted when the backup completed.
It sounds to me like the backup software may have gotten smarter and will automatically use the most recent snapshot if it can’t create one itself.
Jeff Kennedy Qualcomm, Incorporated QCT Engineering Compute 858-651-6592
From: Fred Grieco [mailto:fredgrieco@yahoo.com] Sent: Tuesday, November 23, 2010 11:35 AM To: Kennedy, Jeffrey; Jeremy Webber Cc: toasters@mathworks.com Subject: Re: NDMP backup of snapmirror target
I was doing the my most recent testing on Ontap 7.3.3, using Backup exec 12.5. The NDMP backup worked. I selected the volume for backup, as Backup Exec will not let me specify a particular snapshot. I monitored the snapshots in System Manager-- it looked like the NDMP process used the most recent snapshot, as it put it in Busy/Dump status.
Fred
________________________________ From: "Kennedy, Jeffrey" jkennedy@qualcomm.com To: Jeremy Webber Jeremy.Webber@al.com.au Cc: Fred Grieco fredgrieco@yahoo.com; "toasters@mathworks.com" toasters@mathworks.com Sent: Tue, November 23, 2010 2:14:33 PM Subject: RE: NDMP backup of snapmirror target I would be very interested to hear from Netapp contributors if NDMP backups of volume snapmirror’s has changed. My education at the time was that volume level snapmirror’s are RO for all blocks, which means inode pointers could not change since that meant a change to blocks *in* the volume.
QSM/Snapvault has never suffered from this issue.
Jeff Kennedy Qualcomm, Incorporated QCT Engineering Compute 858-651-6592
From: Jeremy Webber [mailto:Jeremy.Webber@al.com.au] Sent: Sunday, November 21, 2010 6:22 PM To: Kennedy, Jeffrey Cc: Jeremy Webber; Fred Grieco; toasters@mathworks.com Subject: Re: NDMP backup of snapmirror target
Maybe there were limitations in earlier versions of OnTAP but I can confirm that we do tape backups, via tape, from a snapmirror destination without having to break the snapmirror relationship.
A snapshot is automatically created in the snapmirror destination for the duration of the NDMP job.
I can't recall if subsequent snapmirror updates fail during the backup and am not able to test this right now.
OnTAP 7.3.2.
-jeremy
On 17/11/2010, at 6:11 AM, Kennedy, Jeffrey wrote:
Things may have changed in OT since I last was concerned with tape backups but as I recall a snapmirrored *volume* can’t take the backup snapshot because it’s RO. So you point the backup software at the newest snapshot in the RO volume and back up that view.
The only reason the NDMP backup makes a snapshot is to guarantee consistency. An existing snapshot already has that.
Jeff Kennedy Qualcomm, Incorporated QCT Engineering Compute 858-651-6592
From: owner-toasters@mathworks.commailto:owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Fred Grieco Sent: Tuesday, November 16, 2010 6:26 AM To: toasters@mathworks.commailto:toasters@mathworks.com Subject: NDMP backup of snapmirror target
I am snapmirroring several volumes to a DR site, and I would like to do tape backups at that site. How should I do them? Can I use NDMP?
It seems like I can't do straight NDMP because the replicated target is read-only. I am currently creating flexclones from snapshots existing in the volume (nightly.0...) but flexclone then locks this snapshot and snapmirror will fail to update ( I'm not sure if this happens at the next update or when the source system attempts to remove that snapshot and copy it over... I wasn't watching).
What do you generally do to get snapmirrored volume data to tape?
TIA,
Fred
-- Jeremy Webber Senior Systems Engineer Animal Logic Pty Ltd T: +61 2 9383 4837 F: +61 2 9383 4801