We've used subfiles successfully for large files, but only because we
were able to put large amount of fileclass disk behind our primary
diskpools.  If you do that, collocation and how many subfiles pieces
there are becomes a moot point.
Don't go there if you're using tape as the back end.

Steve Schaub
Systems Engineer, Windows
BlueCross BlueShield of Tennessee

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Mark Stapleton
Sent: Wednesday, January 21, 2009 10:07 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Unexpected behavior - Win2k3, TSM 5.4, NTFS
permissions

From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Kinder, Kevin P
I haven't used the following two features in combination yet, so a
question:

If I were backing up using subfile and collocation, would this alleviate
the problem of the subfile backups being spread over many volumes?

Marginally. You'd still have to wander an individual tape (or tapes) to
pick up all the deltas that the subfile process created. This will
greatly delay restores, particularly large restores of many small files.
Also, remember the file size restrictions enforced by subfile work.

As I mentioned earlier, adaptive subfile backup technology was
originally designed to accommodate small-ish backups coming through
narrow WAN pipes. In the meantime, collocation will increase tape volume
usage, overall tape traffic, and daily migration and reclamation
processes.

As is always true in life, you end up having to rob Peter to pay Paul.

--
Mark Stapleton
System engineer, CDW

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