trouble with mysql replica and 3ware 9590 RAID controller



Hello!

I've encountered a trouble with very low performance of mysql replica on 9590SE controller. as replica, mysql performs only updates and no selects at all, but I cannot be satisfied by performance of this replica, because of 100% busy of disk array with about 3-4 MBytes/s activity, e.g. iostat -x:

extended device statistics
device r/s w/s kr/s kw/s wait svc_t %b
da0 55.5 78.9 928.1 2047.6 1 108.0 98


and more sadly, disk wait time increases sometimes to 300 seconds and more.

I've made NCQ on, changed strategy to perfom, but nothing helps. If I stop mysql, then I can write about 30-40 MBytes per second to this array (raid 1)

And I should say that this replica worked just fine on slackware with p3 866 and IDE disks.

Mysql version is 4.0.27, twa firmware is 3.04.01.010

--
SY, Marat
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