On Friday, 6 Sep 1996 Andreas Floeter <Andreas.Floeter AT AIRBUS DOT DE> wrote:

>Your throughput is (8*1024)/(40*60) = 3.413 MB/sec. That is 1/3 of the
>theoretical performance of the drives. To which degree is your database
>filled? Have you seen faster values? We are considering buying 3590, so I
>am curious about all informations I can get.

The very best performance we get is about 5 MB/sec on BACKUP STG with a
large average filesize (greater than 1 MB). The very worst is about
1 MB/sec on MIGRATION with a very low average filesize (less than 80KB).
Our (full) DB backup  takes about an hour currently - about 11-12 GB.

We have a 4-frame 3494 library and 4 3590 drives - all on dedicated
SCSI FWD channels (we plan to double up drives on the channels in the
future).

We also have two 7137 SCSI RAID-5 arrays which hold the ADSM DB, we
allocate alternate 2GB DV volumes on each array. We also have SSA disks
on which we have storage pools, etc. - about 66 GB dedicated to primary
disk pools.

We are using R24 architecture at present and will switch to R30 4-way SMP
around the end of the year. We utilise all but one of the 16 channels
currently.

We have not had a trouble free year with the hardware - we have had several
disk failures, repeated problems with the load/unload mechanism on one of
our 3590s and we have lost 6 3590 tapes in service (out of about 600 in
regular use) - 3M are investigating these.

On the whole though we have been pleased with the hardware performance.

We have not had a trouble free year with the software either - but there
is every hope and indication that ADSM will get faster in the next year
or so ... and will be better able to make optimal use of the high
performance hardware we bought.

>See we just switched to ADSM server 2.1.5.9 yesterday running on a C20
>with AIX 4.1.4, I am also interested in what kind of problems have you
>seen?

TODAY for us! Hope ours goes as well as yours!

Regards, Sheelagh

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Sheelagh Treweek                         Email: sheelagh.treweek AT oucs.ox.ac 
DOT uk
Sheelagh Treweek                         Email: sheelagh.treweek AT oucs.ox.ac 
DOT uk
Oxford University Computing Services     Tel:   +44 (0)1865 273205
13 Banbury Road, Oxford, OX2 6NN, UK     Fax:   +44 (0)1865 273275
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