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?

----------------
Kevin 

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Jason Clarke
Sent: Tuesday, January 20, 2009 7:16 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Unexpected behavior - Win2k3, TSM 5.4, NTFS
permissions

Hi Mark,

Thanks for your comments. I've decided to not go with subfile backups
because (from training late last year) I understood that a 1MB file
could be backed up over many volumes, thus being insanely slow to
restore.

The spike of 120GB isn't a huge problem. Currently, we're only have
about 2TB of data that needs backing up. We've installed a IBM TS3200
(44 slots) with 2x LTO3 drives. Along with a 500GB disk pool that
clients spools to first. At 3 backup revisions of most of the data, we
should have room for expansion.

However, on thinking about that 500GB, I'll probably up it as one of our
servers is expected to grow beyond that in size.

Thanks again for the comments.

Cheers,

Jason

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Mark Stapleton
Sent: Wednesday, 21 January 2009 10:51 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
Jason Clarke
Last night, the client backed up 129GB, which is about 125GB more than
normal.

On any given day, during the holidays, theres about 2-3GB of changed
files.

However, I did change a permission on a directory/folder tree that
contains 125GB of files.

I'm guessing TSM has backed up the whole file because of the permission
change. I'm guessing this is because subfile backup isn't being used
here. If subfile was turned on for that client, would it reduce the
amount of data it decided to backup?

Yes, subfile backups would decrease the amount of data you would have
backed up. However, you will eventually have to back up the entire set
of files eventually, because subfile backups allow a limited number of
deltas to be backed up, and will only affect files greater than 10kB and
less than 2gB. Also keep in mind that if you have, say, 100,000 files,
and you have 5 deltas for each file, you're going to have to make
restore 600,000 locations on tape--1 for the last full backup of a given
file, and 5 for its subsequent deltas. Subfile restores are very, very
slow, and are more designed to accommodate backups across slow (i.e.,
T-1) bandwidth pipes.

TSM treats files as whole entities. When you change permissions on a
file, TSM will back it up again. Might I suggest that you stage such
mass changes so that you don't get hit with such a spike again?

--
Mark Stapleton
System engineer, CDW

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