Snapvault just copy snapshots over to the destination volume from the source volume?

[netappmagic]

I basically understand how snapvault works and procedures between the source filer and destination filer, basedline has to be created first.

I have one question though:
Assuming I created a hourly schedule on the source volume, it will be 5 retention and between 8am-8pm. On the destination volume, I created a hourly schedule as well. Let's say I keep 10 retention and between 8am-8pm

In the end of the day, I have 10 snapshots, they are respectively taken at 8,7,6,5,4,3,2,1,12pm, and 11am. My question is, are these 10 snapshots are just identical copies which are taken at the same time on the source filer and transffered from the source filer?

Please help to clearify this concept. Thanks!

[netappmagic]

Anybody got the chance to looking into my question? Thanks!

[liviu_ianasi]

I don't have a clear picture of the process of snapvault but don't think it's just a copy of snapshots. I've checked my snapvault volume and snapshots from source and destination have different sizes.

Anyway I don't enable snapshots on the source volume. Only snapshots created by the snapvault schedule.

[SeanLuce]

Mr. Magic,

SnapVault does not copy Snapshots from the primary to the secondary.  What you are describing is more aligned with how SnapMirror functions.  With SnapMirror, the destination is a mirror copy of the source (including Snapshots).

SnapVault is a bit different.  With SnapVault, you have 3 schedules to maintain:

Schedule 1: Snapshot schedule on Primary (source)

Schedule 2: SnapVault update schedule (the schedule to update the active file system (AFS) on the secondary from the primary (primary -> secondary)

Schedule 3: Snaphot schedule on Secondary (target)

This allows the primary and secondary to have unique snapshot copies and retention periods.  It is typical to have a much longer retention period on the secondary.

Check out section 3 of the SnapVault Best Practices guide for a more in depth explanation: http://www.netapp.com/us/system/pdf-reader.aspx?pdfuri=tcm:10-61092-16&m=tr-3487.pdf

[netappmagic]

active file system (AFS) on "the secondary"? I thought there are only snapshots on the secondary, active file system exists only on the primary. I would like to know more granularly on what data really copied over to the secondary if they are not really snapshots from the primary. I have read the attached document tr3487, still could not understand it fully...

[SeanLuce · Accepted solution]

"I thought there are only snapshots on the secondary"

It is impossible to have only snapshots.  Those snapshots must point to real data blocks.  Remember, a NetApp snapshot is a point in time capture (via pointers) of the entire file system, not a delta.

The first part of setting up a SnapVault relationship is a baseline.  This baseline is a 1:1 copy of the primary's AFS.  Think of it as an incremental forever backup.

1. Initial Baseline Transfer (Monday Morning)

2. Secondary Snapshot (Monday @ 9pm)

3. Update from Primary to Secondary AFS (Tuesday Morning)

4. Secondary Snapshot (Tuesday @ 9pm)

5. Update from Primary to Secondary AFS (Wednesday Morning)

6. Secondary Snapshot (Wednesday @ 9pm)

The update from primary to secondary is only the data that has changed since the previous update.

I hope this helps...

Sean

[netappmagic]

Sean, you have cleared up my mind!