Just a quick one... I'm running 2 adsm sites each has an IBM 3494ATL
with just two 3590 drives (each atl). I would rest easier if I had 3
in each ATL but the $46,000 price tag required me to cough up
justification... I really couldn't...
The two servers were built to cover each others load in the event of
failure of one (machine, atl, communications, etc) so I have extra
capacity in the disk pools and with the 10/30GB 3590J tapes in the atl
WOW, talk about extra capacity...
But those 3490E's are @ 2GB so you will be crunched a little there...
When my second adsm environment was being built 3590's were in low
supply and I had to rob one from the existing atl for the new ATL...
we ran that way for @ 3-4 weeks... I never needed to but I always had
the option to recycle with use of dasd... I was a little worried about
the backed up recycles when we got the second drives. NO PROBLEM...
recycles are real quick to give up the drives to other requests...
Once when a client had bought a bunch of cheap 3rd party 9GB drives
for their machine... they had 1 go bad, then the next day 2 more went
bad... recycles were running but gave up the drives... I did see a
little thrashing in that the client was restoring bits&pieces at a
time so when he would pause for 10 or 15 minutes a recycle would start
up, get some data moved then that client would stick in his next
restore and the recycle would get bumped again...(client was restoring
one db env at a time)
anyway... with @80 clients containing 1+ terabyte of file systems I
have no problem with only 2 drives BUT everything I'm running with
is FAST & HIGH CAPACITY... fddi links to 95% of clients, 3590 tapes,
and a couple drawers of SSA 4.5GB dasd for disk pools.
We have already gone +50% origional guess-'da'-mation of covered nodes
and are pulling in other servers (with independent backup solutions)
so we can redeploy their equipment in other areas...
This is business critical data so when I say no problems here... I
mean NO PROBLEMS.
gotta go,
later
Dwight
______________________________ Reply Separator _________________________________
Subject: Reccomended # of tape drives???
Author: ADSM-L at unix,mime/dd.RFC-822=ADSM-L\@VM\.MARIST\.EDU
Date: 5/23/96 3:32 PM
All,
We are trying to gather some information on ADSM, and the
hardware needed to support it. Our site (briefly) consists of UNIX,
Novell, Windows/NT, and some OS/2. Total storage across all (30 or so)
servers is approaching 160-170GB. We are looking at an RS/6000 F30
with Fast Ethernet and about 12GB of disk reserved for ADSM storage
pools to act as a dedicated ADSM server. Our tape subsystem will
consist of _TWO_ StorageTek Timberline 3490E tape drives on an STK
Wolfcreek silo (840 slots). Do you think two drives will be enough to
handle the tape reclaim processing and still allow for restores during
the day? Would you recommend three or more drives initially? Given the
info above, can someone take a stab at approximating the time for tape
reclaim processing? Any help would be greatly appreciated.
Tom McKnerney
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