So if I have a list of SSIDs I can gain some performance improvement if
I first parse the list and seperate it into 2 lists; 1 complete savesets
and 1 spanning?
This implies a case I may have now ...alist of savesets where:
saveset 0001 = tape A, complete
saveset 0002 = tape A, header
saveset 0003 = tape A, complete
saveset 0002b = tape B, tail, rest of 0002
..and the clone may have to mount tape A again to read saveset 0003 after
reading 2 tapes for saveset 0002??
Robert Maiello
Thomson Healthcare
On Mon, 29 Sep 2003 11:09:15 -0500, Ed Skolnik <eskolnik AT INTERPUBLIC DOT
COM> wrote:
>George,
>I quote Legato PSE
>
>" He said that, from a performance perspective, it's best to make sure that
the fragments (head, middle section or tail) are on
>contiguous media files on the volume. Tape rewind and positioning is
expensive and detrimental for performance and should be
>avoided during the read part of the clone. Needless to say if all the
fragments are contiguous on the same volume (no spanning) the
>search for the segments and clone would be the fastest. "
>
>What I do is clone complete saveset's 1st by volume (mminfo -omo ) with the
sumflags = c , then I clone any saveset that spans
>volumes.
>
>
>
>mminfo -t${fromdate} -omo -q"$minusq" -r'ssid,sumflags' | tail +2 | \
> while read ssid sumflag; do
> sumflag1=$(echo $sumflag | cut -c1)
> case ${sumflag1} in
> "c")
> # The complete saveset is on this volume, so do it 1st
> echo $ssid >> $tmpssidonly
> ;;
> "h")
> # Only the header is on this volume
> echo $ssid >> $tmpssidonly_span
> ;;
> *)
> ;;
> esac
> done
>
>-----Original Message-----
>From: George Sinclair [mailto:George.Sinclair AT NOAA DOT GOV]
>Sent: Friday, September 26, 2003 1:39 PM
>Subject: Re: Faster Cloning. By saveset or volume?
>
>
>I seem to recall that this got into this issue of de-multiplexing versus
maintaining the multi-plexing. Then again, that may be have
>been the difference between running the nsrclone command with a list of
saveset ids (on the command line with -S or via an input
>file as -S -f file) versus iterating over the list one at a time. I think
if you iterate it, the savesets would have to be
>un-multiplexed, but if you don't iterate it one at a time then the
multi-plexing is preserved. If that's true, then it seems to me
>that cloning the entire volume would have to be faster because it would not
have to de-multiplex anything, but if you did it by
>saveset, one at a time, then it would, unless you ran it using an input
file with all the savesets in there.
>
>So, my question would be: is running nsrclone with an input file that
contains all the savesets tantamount to cloning the whole
>volume in terms of over all time. In other words, which of the following is
>faster:
>
>nsrclone -s server -b pool volname
>nsrclone -s server -b pool -S -f file
>
>where file contains all the saveset ids on the volume.
>
>I mean, both operations should amount to the same thing, but I'm thinking
that cloning the volume using the first command is easier
>and could not be slower than the second.
>
>George
>
>"Novello, Guy" wrote:
>>
>> Hello Everyone,
>>
>> I seem to remember a discussion over which was the faster way to
>> clone. I am currently using the ssid, but I am thinking it may be
>> faster cloning the volumes.
>>
>> Has anyone tested this?
>>
>> Thanks in Advance!
>>
>> Guy
>>
>> --
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