Mark,
Good point, what you may have heard being a problem was using Network Attached Storage
(NAS) for TSM volumes, in which case TSM considers sequential media. i'm talking about
using Direct Attached Storage (DAS). Since DAS is consider random access by TSM there
is no need to do reclamation on the disk volumes. Expire Inventory reduces the size of
the disk volumes automatically. ISCSI would also be seen as random access by TSM since
it's block I/O and not file I/O like NAS.
The pros are disks arrays are much cheaper than tape libraries and more reliable,
everything runs faster, and much less maintenance.
There's no cons to using disk for your backup pool except one and it's a big one, if
you lose a 1TB array it's bear to restore from the copypool, especially in our case of
having a small tape library. That's why i recommended Pat to keep his large tape
library and just grow his disk storage. Our disk expansion cases (IBM Exp300's) use
raid 5 and have plenty of hot spares with redundant everything and are plugged into
two dedicated separate AC circuits.
We have a number of Policy Domains ranging from 14 to 30 days retention period. i do
use excludes heavily, especially apps that create large index files that have to be
recreated after a restore anyway.
If you have another questions please let me know.
john
-----Original Message-----
Date: Thu, 11 Apr 2002 11:12:43 -0400
From: "Kovacs, Mark" <[EMAIL PROTECTED]>
Subject: Re: Using Disk in place of tapes for copy pools
John,
How many versions do you keep and how does reclamation happen, if it
does ? We are interested in setting up something like this and would like
to know more of the pros and cons. We've seen prior conversations about
issues on reclamation.
Any and all information would be appreciated.
thanks,
mark
-----Original Message-----
From: John Underdown [mailto:[EMAIL PROTECTED]]
Sent: Thursday, April 11, 2002 8:48 AM
To: [EMAIL PROTECTED]
Subject: Re: Using Disk in place of tapes for copy pools
Pat,
We been using a all disk backuppool for a number of years now. It's grown to
3TB (4 expansion cabinets with 14 73GB drives each and each set to raid 5),
we just keep adding disk expansion to server as we need more storage. We use
a small LTO library for the copypool. We backup 360 servers (80 to 100 GB
total) nightly and growing. The TSM database is 10GB sitting on raid 10 with
15K rpm drives (very fast) , i also defrag the DB monthly. This is a dream
setup and works very well, restores run in the blink of a eye. I run the TSM
server by myself as a part-time duty.
I would suggest just growing your disks storage on your backuppool to at
least 1 TB to keep backups and restore running fast, allowing older data to
migrate to your existing tape library. Now a days disks have both a
performance and price advantage over tape.
If you have any other question please let me know.
john
Synovus
Columbus, GA
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