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Re: [Networker] How does nsrclone order a list of SSIDs for cloning?
2009-12-22 23:20:55
bbartick wrote:
We recently rolled out a VTL and I'm in the process of scripting the cloning
process. From the testing I've done, it seems as though nsrclone does not clone
the SSIDs in the order you pass to the command.
I'd love to clone the oldest savesets first so that I can roll them off the VTL
first.
I was thinking I could do something similar to:
mminfo -ot -q "pool=VTL1,copies=1,!incomplete,savetime<21 days ago" -r ssid -->
output to a file $FILE
I've run into this many times. I think it wants to best preserve the
interleaving as it is on the original/source tapes. As a result, if, for
example, five save sets are wrapped (multiplexed) together on the
original volumes then that's how it wants to leave those when it writes
those to the clones.
If you think about it, this is more efficient; otherwise, it has to
extract each one out separately, and that adds a lot of time, not to
mention the fact that it might end up returning to the same tape (in
your case, virtual tape volume) multiple times during the entirety of
the operation. Now, in the case of a VTL, it might be moot. My
experience is limited to physical tape, but NW thinks the virtual tapes
are in fact tapes, so they'll behave the same way as actual tape, right?
And they'll be subject to the same restrictions?
However, if you instead run separate nsrclone commands for each ssid
then that will force it to clone each one separately. It has to. And I
don't see how that would eat up more space on physical clone tapes than
it would if it preserved the interleaving, but it will certainly take
longer and is more inefficient. That may not be a viable option for you,
though, and I'm sure you already considered that.
Then I will clone the ssids
nohup nsrclone -b "$POOL" -y "$RETENTION" -J "$NODE" -S -f $FILE &
I was surprised to see my savesets aren't being cloned in the order of the
savesets in the file.
Can anyone tell me how nsrclone determines which savesets will be cloned first?
I think the way I mentioned above is what it does. I think this is also
true if you pass it the ssids on the CLI as: '-S ssid1 ssid2 ssid3 ...'.
Again, though, all bets are off in terms of how much additional slowness
would be incurred if you're using virtual tape and you clone them
separately.
I hope someone else will chime in on this because I've been wrong a lot
lately ... sigh.
George
Thank you,
Brett
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