[rescue] RAID q - lots of 8K transactions

Curtis H. Wilbar Jr. rescue at hawkmountain.net
Fri Jun 20 11:11:18 CDT 2003

>From: "Patrick Giagnocavo +1.717.201.3366" <patrick at zill.net>
>I think that this list is probably the right one to ask...
>I am considering moving a customer to Solaris 9 (maybe Sol9/x86).
>Here the dilemma I have:
>There are a lot of 8KB transactions due to the use of Postgres.  As a
>result, what matters is not total disk bandwidth but how many
>transactions per second.  Even the fastest disks don't have what I
>Sol9 has the disksuite tools - what would you recommend as a setup for
>best results?  A RAID 10 config (mirrored stripe)?

If speed is an issue, that is probably your best bet.  Internally (as
I recently found out here on the list), disksuite will internally optimize
a mirrored stripe as a stripe of mirrors (better fault tolerance).  This
is of course assuming all the disks are the same and partitioned the same,

You can adjust your stripe size of course, and in this case, 8KB may
be the optimum.  You probably will want to use a trans device if this is
a big file system, so should it go down and come back up it will do so
quickly rather than a long fsck check.  Although how that will impact
your transactions I don't know (probably will only have an impact on
writes.... but the trans might speed those up as it will get written to
the trans device then ODS will "flush" the trans to the striped mirrors
(configured as mirrored stripes)....

You could also go with hardware raid doin the same config, although disksuite
should probably do what you want.

I don't setup production Solaris boxes without using disksuite (or hardware
raid) any more.  I sleep easier now :-)

-- Curt

>rescue list - http://www.sunhelp.org/mailman/listinfo/rescue

-- Curt

Curtis Wilbar
Hawk Mountain Networks
rescue at hawkmountain.net

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