That's way off.
There are so many tape technologies available, a single "rule of thumb" is
meaningless. Also it is very dependent on how you configure your TSM...
how many storage pools, do you make offsite copies for all data, are you
collocating, etc.
But, here's a real-world example (mine):
We use a mixture of DLT-IV (native capacity 40GB per cartridge) and LTO2
(native capacity 200GB per cartridge).
We have hardware compression on, and client compression off.
We use collocation for "business-critical" systems.
We are backing up about 30 Unix servers and over 200 Windows servers.
(current license in use count is 296)
We do daily backups for virtually all clients.
We have a total of 500,019,525 Megabytes backed up... that's about 500
Terabytes.
We have 1,065 cartridges onsite... 129 DLT's, and the rest LTO2
We have 1,439 cartridges offsite (DRM managed)... 737 DLT, the rest LTO2,
and most of these are far less than 50% full.
====> So, 500 Terabytes on 2500 tapes, and with some reclamation we could
bring that down significantly.
I consider our backup data to be average, or typical, if there is such a
thing... almost half is email (Lotus Notes), a quarter is Oracle database,
and a quarter is flat files (Windows and Unix).
As for growth, we backup almost a terabyte a day, and our current LTO2 tape
consumption is about 140 cartridges per month... but that includes both
onsite and offsite copies... so 60 TB per month on 140 tapes. This is a
high figure because we are temporarily (I hope) not allowed to delete
anything... so no files are expiring.
We don't use DLT anymore, just waiting for the old ones to expire.
Hope this helps...
Happy Holidays!
Robin Sharpe
Berlex Labs
|---------+--------------------------->
| | "Lepre, James" |
| | <JLEPRE AT NECA DOT ORG|
| | > |
| | Sent by: "ADSM: |
| | Dist Stor |
| | Manager" |
| | <[email protected]|
| | T.EDU> |
| | |
| | |
| | 12/22/2004 09:45|
| | AM |
| | Please respond |
| | to "ADSM: Dist |
| | Stor Manager" |
| | |
|---------+--------------------------->
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|To: ADSM-L AT VM.MARIST DOT EDU
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|cc:
|
|Subject:
|
| Re: Tape Questions
|
>----------------------------------------------------------------------------------------------------------------------------|
Hello All,
I have a question is there a rule of thumb for how many tapes will
be used, when using TSM. I heard that for every Terabyte that is backed
up, 1000 tapes could be used. I was just wondering, if anybody knew
something different. I keep 2 versions for 7 days
Thanks
James
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