Hi Simon,

Is it possible to backup just the .snapshot and then perform a restore from this data?

Yes, when restore looks at the backup tape it doesn't see the .snapshot/weekly.0 preamble so the backup to NetApp looks the same as if you hadn't specified a snapshot. As Steve pointed out some of the NDMP backup applications remember this preamble and need to be redirected on restores.

I am looking for ways to speed up the backups and this seems to be a possible option.

As our capacities grew snapshot create & delete times started to increase (pre 6.0 releases). With Data Ontap 6.0 we re-engineered our snapshot implementation and re-introduced "instantaneous" snapshot creation. Dump either via rsh, console or NDMP only ever backups from a snapshot either a named snapshot or one it creates (& manages) itself. If you are running a pre-6.0 release then I can believe you might see less impact on backups by using a named snapshot either from the snap sched set (we don't normally recommend you use these snapshots for dump because they get updated on the snap sched schedule and dump locks the snapshot its working on, e.g. the two schedules can conflict meaning you miss a valuable snap sched update) or created by the user using rsh snap create. In the past we've seen customers create a snpshot rather than let dump create it since they are going to perform multiple qtree or sub directory backups and just want one snapshot to be created.

In Data Ontap 6.0 or beyond, there should be no noticable difference using dump on a named snapshot or when it needs to create its own snapshot. /etc/dumpdates is a database that dump uses to remember the time the last backup was done on the path used, so on an incremental dump we simply create a new snapshot, pick up the time of the last dump and then read out all files & directories in the new snapshot that have been modified since that timestamp.

But maybe the time you are saving is actually on quiescing Clearcase and the VOB data and not on the snapshot creation. I wasn't clear.

Cheers, Grant

=========== grant@netapp.com ========== Grant Melvin === === Software Development Manager === === Data Availability & Management === |\ | __ ___ /\ __ __ === Network Appliance === | \ | |__ | /__\ |__| |__| === 475 East Java Drive === | | |__ | / \ | | (R) === Sunnyvale === === California, 94089 === === Tel:(408)822-6761 =========== Network Appliance ========== Fax:(408)822-4578

-----Original Message----- From: Clawson, Simon [mailto:simon_clawson@mentorg.com] Sent: Wednesday, April 25, 2001 8:39 AM To: 'Traitel, Eyal'; 'E.J. Jantz'; toasters@mathworks.com; Clawson, Simon Subject: RE: snapshot backup

That sounds like exactly what I meant. We currently backup / and everything below that. What I was hoping I could do was backup /.snapshot/weekly0 and then use this as my full backup. I user Veritas NetBackup to fire off the NDMP job on the filer, so I guess I would need to modify the backup path to /.snapshot/Weekly0?

Simon

-----Original Message----- From: Traitel, Eyal [mailto:eyal@netapp.com] Sent: Wednesday April 2001 16:29 To: 'E.J. Jantz'; toasters@mathworks.com; simon_clawson Subject: RE: snapshot backup

Our snapshots are to be more exact "copy on new write" as opposed to "copy on old write", with the advantage of no penalty at all in terms of performance of taking the snapshot, and performance of filesystem after taking it (think of "copy on old write" - filesystem needs to read old block, write it in the backup location, then write the new block in old place - that's 3 I/Os. For us it's only 1). We do not have to go back to specific locations on the disk, and that's a real advantage in terms of performance.

In regards to full compared to snapshot - with NetApp, it's probably always better to backup snapshots, as they are point-in-time - when you've started your backup at 19:00, all of it will be consistent to 19:00 sharp, unlike traditional backup, which data changes while you backup... So - if you get me right - you can even do full backup from a snapshot...

On Legato - I think you can just mention .snapshot/hourly.0 for example in your path of backup. If you use NDMP, you anyway backup a snapshot, as the filer's dump creates one automatically for you.

Hope it somewhat helps, Eyal.

---

eTraitel - I'm the new eBuzzword around !!!

Eyal Traitel - Filer Escalation Engineer CNA, MCSE, CSA, LCA, NetApp CA

           Network Appliance BV
           Holland Office Center
           Kruisweg 799b
           2132 NG, Hoofddorp
           The Netherlands

Office: +31 23 567 9685 Cellular: +31 6 5497 2568 Email: eyal@netapp.com

---

Get answers NOW! - NetApp On the Web - http://now.netapp.com

-----Original Message----- From: E.J. Jantz [mailto:ej_jantz@bswintl.com] Sent: Wednesday, April 25, 2001 3:55 PM To: toasters@mathworks.com; simon_clawson@mentorg.com Subject: Re: snapshot backup

just a question: If the 'snapshots are "copy on writes' doesn't that mean that a backup of .snapshot is equal to and functions as a full backup? If not, can Legato using a NFS mount on a unix server capture just the info the .snapshot uses? If so, how?

thanks...

EJ Jantz, IST Dept. BSW International One West Third, Ste 100 Tulsa, OK 74103-3505 918 582-8771 ej_jantz@bswintl.com 918 295-4166 918 587-3594 fax

...

...

...

"Clawson, Simon" simon_clawson@mentorg.com 4/25/01 4:32:08 AM

Is it possible to backup just the .snapshot and then perform a restore from this data?

I am looking for ways to speed up the backups and this seems to be a possible option. It was suggested to me by a colleague as a method of backing up Clearcase VOBS, but would it be viable for the whole filer. Of course I would need to run a full backup at tleast once a month, but this would help me speed up most of my weekly runs.

Any ideas/suggestions/views?

Simon

Simon Clawson HDS Team Systems Administrator Mentor Graphics Uk Rivergate London Road Newbury Berkshire RG14 2QB <<Clawson, Simon.vcf>>