ADSM-L

Re: Tape or Disk? Sizing question

1997-04-01 18:12:15
Subject: Re: Tape or Disk? Sizing question
From: Tom Kauffman <namffuak AT SKYENET DOT NET>
Date: Tue, 1 Apr 1997 18:12:15 -0500
At 04:38 PM 4/1/97 CST, you wrote:
>Tom,
>
>Sorry, I don't have any restore rates to give you. Under normal
conditions, backing up across an SP switch, we're getting up to 16GB per
hour. I just want to pass on some capacity planning tips.

Thanks, Jim -- is this direct to tape speed, or are you staging to disk?

> You won't be able to go too far with the ACF and one drive. Tape
reclamation >is one reason. There isn't even an 8mm to move data to, so
you'll be going >through a lot of tapes. Assuming that you decide on a 3494
robotic library and >2 or more 3590s, check the number of open slots you
have left on the wide >node. We had to move our ADSM server to a high node
so we could run 4 drives >on separate SCSI cards. With 4 drives, we can do
reclamation or offsite copies >concurrently with our backups (or
reclamation and offsites concurrently). >Those are just a few things to
look at.
>
Oh, we *know* one drive isn't enough! Our problem is *proving* that two
won't carry the load either -- and that *three* 3590s, each with an ACF, is
kinda dumb. I have enough slots (if I remember corectly), and if I don't,
I'll be forced to two tape drives per SCSI interface. This project is
already showing signs of severe budget strain -- and to go to a high node
I'd need to add a third frame and switch.

TomK
Tom Kauffman
Sr. Technical Advisor
NIBCO, Inc.

namffuak AT nibco DOT com
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