I have been using a 3ware 9690se sata card with raid5. I have been running Centos using xen and have had no problems. I wrote my virtual machines to the raw raid5 drive. Its seems to have worked fine for me. On Thu, Sep 24, 2009 at 9:18 PM, Philip Gwyn <liste at artware.qc.ca> wrote: > Hello, > > I have strange behaviour on a server that I can't get a handle on. I have > a > reasonably powerful server running VMware server 1.0.4-56528. It has a > RAID5 > build with mdadm on 5 SATA drives. Masses of ram and 2 XEON CPUs. But it > stutters. > > Example : fire up vi, press and keep finger on i. After filling 2-3 lines, > the > display is stopped for 2-12 seconds. Then they continue. This happens > even on > the host OS, at the console. > > Host system running CentOS 5.2 x86-64: > > CPU : 2x Xeon E5430 @ 2.66GHz > RAM : 24GB > Mobo : DSBV-DX > HD : 5 x SATA ST3750330AS 750GB in RAID5 > > There are 5 VMs, detailed at http://www.awale.qc.ca/vmware/stj1.txt to > make > this mail shorter. > > Seems to me this system should be more then adequate to handle the load. > > This is what vmstat on the host looks like when the server is "unhappy" : > http://www.awale.qc.ca/vmware/vmstat.txt > Spending a lot of time in 'wa', but 'bo' and 'bi' are miniscule. > > The problem seems like a disk problem. I grow to suspect that SATA isn't > ready > for the big time. I also grow to dislike RAID5. > > Questions : > > - Anyone have a clue or other on how to track down my bottle neck? > > - SATA NCQ is limited to 15 queue depth. Is this per-SATA-port or > per-SATA-chip? Or does this question make no sense? > > - I realise there are more recent versions of CentOS out. Are there > specific > items in the changelogs that would affect my problem? > > Thank you for any help, > > -Philip > > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt at centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos-virt/attachments/20090925/7b1db5e9/attachment-0006.html>