>Can you quantify how much the write cache in the 7137 helps?  Also, when
>you tried the 3137 which RAID version did you use (i.e., 0 or 5)?  Any
>other details you can share would be greatly appreciated!

Paul,

We use 7137 with RAID-5.

Timings were done for client backup (selective) and delete filespace (for
a pure DB operation). I can't lay my hands on all the figures just now, and
some of them could have been more complete tests, but some examples:

7137: selective backup, 2 clients, 13000 files/250MB  09mins:26secs
SSA:  selective backup, 2 clients, 13000 files/250MB  13mins:34secs

SSA:  delete filespace, 2 processes,  464 files/sec
SSA:  delete filespace, 1 process,    960 files/sec

7137: delete filespace, 2 processes,  992 files/sec
7137: delete filespace, 1 process,   1968 files/sec

all with recovery log in roll forward,

and after removing roll-forward:

7137: delete filespace, 2 processes, 1744 files/sec
7137: delete filespace, 1 process,   2736 files/sec


and then I increased BUFFPOOL to about 6MB ... (from 1MB)

7137: delete filespace, 2 processes, 1743 files/sec (with roll-forward)
7137: delete filespace, 1 process,   3895 files/sec (with no roll-forward)


I appreciate that these might seem somewhat incomplete sets of data ...
but I tried LOTS of different things around that time to maximise
performance!

Just to summarise, some of the best things I found out overall:

        - increase TXNGROUPMAX(256), BUFFPOOL(6144) and LOGPOOL(4096)
        - run server processes as single tasks : e.g. don't mix migration
          and backup stg; don't mix migration from different pools, etc.
        - keep DB on 7137
        - try to persuade users not to do client backups whilst the server
          is trying to do migration/backup stg etc (impossible!)
and
        - have as many copies of LOG as you can afford (I worry a lot!)
        - pay the penalty of having roll-forward log - everyone needs it!

Regards, Sheelagh

------------------------------------------------------------------------------
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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