Re: ADSM and 3490E D42 Tape Drive
1994-12-08 18:55:37
On Thu, 8 Dec 1994 15:10:26 CST Larry Sanders, VM System Maintenance said:
>On Thu, 8 Dec 1994 11:50:19 CST Keith A. Crabb said:
>>I have Memorex equivalents of 3490E tape drives and am using the 3490
>>extended length cartridges with data compression on the clients and am
>>seeing about 800M per cartridge. So I'd say 400M is about what you would
>>expect from standard length cartridges. You can store more on the tapes
>>without data compression on the clients if you're willing to pay the
>>network bandwith though. In tests I got about 1200-1400M on a 3490
>>extended cartridge but, we decided to just buy more tapes rather than
>>pay the extra 30-50% of network traffic during a backup/restore.
>It's true that if you turn off data compression on the clients, the ADSM
>server will report that it is putting more data on each cartridge, but
>that is because the server would be writing uncompressed data instead of
>compressed data. Regardless of whether data compression is being done
>on the client or by IDRC, it is still the same amount of data, and should
>require about the same number of cartridges.
Oh, I thought that hardware compression was still generally from 5-20%
better than software compression, depending on the scheme used. We had
figured who cares if we have to buy 20% more cartridges to store data,
it would take a lot of cartridges to equal even one 10baseT hub. If the
data storage is really about the same, I quess we shouldn't have bothered
worrying about it. Alas, live and learn. Fortunately the decision was
driven by network load or I guess I would be much embarrassed.
---
Keith A. Crabb Keith AT UH DOT EDU
Keith A. Crabb Keith AT UH DOT EDU
University of Houston Operating Systems Specialist +1-713-743-1530
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- ADSM and 3490E D42 Tape Drive, Peter Hadikin (HDIP9235)
- Re: ADSM and 3490E D42 Tape Drive, Larry Sanders, VM System Maintenance
- Re: ADSM and 3490E D42 Tape Drive, Keith A. Crabb
- Re: ADSM and 3490E D42 Tape Drive, Larry Sanders, VM System Maintenance
- Re: ADSM and 3490E D42 Tape Drive, Paul Zarnowski
- Re: ADSM and 3490E D42 Tape Drive,
Keith A. Crabb <=
- Re: ADSM and 3490E D42 Tape Drive, Nick Laflamme
- Re: ADSM and 3490E D42 Tape Drive, Leonard Boyle
- Re: ADSM and 3490E D42 Tape Drive, Paul Zarnowski
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