[mythtv-users] NFS + 3ware = slow
bill.peck at gmail.com
Sat Mar 11 17:54:33 UTC 2006
On 3/11/06, James C. Dastrup <jc at dastrup.com> wrote:
> I just got a 3ware 7506-4 based on recommendation from this group.
> I'm having problems with writing to the RAID-5 array over NFS.
> Here's some averaged samples using the cp command:
> Samba (reading): 20 MB/s
> Samba (writing): 20 MB/s
> NFS (reading): 40 MB/s
> NFS (writing): 4 MB/s <---- ??????
> Also interesting, the first 500 MB of data when writing over NFS
> goes at about 50 MB/s, and then it slows to a crawl. RAID-5 array
> is formatted JFS. CPU stays low on both machines. I've tried endless
> amounts of mount options: sync,async, rsize=[1042-32768],
> wsize=[1024-32768], lock, nolock, hard, soft, intr, tcp, udp,
> nfsvers=33, etc. iperf is showing a raw transfer rate of 66 MB/s.
> Has anyone seen anything similar? Does anyone know any debugging
> tools or commands so I can see exactly where the slowdown is
I owned a 3ware card at one time.. I ran it with 4 ide drives in a raid 0.
Worked great. But... Running in a raid 5 config is horrible..
Check out this bugzilla at Red Hat for the horror of these cards..
I now own a Promise Sata controller which cost me $40.00 and yes it uses my
CPU for raid 5 but at least I get great perfomance from it and I didn't
spend $300-$400 for a useless card.
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> mythtv-users at mythtv.org
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