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Re: nfs/local performance with software raid5 and xfs and SMP

To: "linux-xfs@xxxxxxxxxxx" <linux-xfs@xxxxxxxxxxx>
Subject: Re: nfs/local performance with software raid5 and xfs and SMP
From: Tru Huynh <tru@xxxxxxxxxx>
Date: Thu, 19 Jul 2001 15:40:14 +0200
Organization: Institut Pasteur
References: <3B55E49E.5B4B6CEF@pasteur.fr> <4.3.2.7.2.20010719111805.03d75be0@pop.xs4all.nl> <3B56AD91.FA721B93@pasteur.fr>
Sender: owner-linux-xfs@xxxxxxxxxxx
Hello,

It looks like a kernel SMP issue more than a 3ware driver
problem.
- I have tried the following SMP kernels:
2.4.3-xfs-1.0.1 and 2.4.7pre8 cvs version which include
the same 3ware 3w-xxxx driver. (I have not yet flash the firmware).
- I can see it on a plain IDE raid5 partition.

I will now flash the 3ware card firmware. but I don't
know what that can change...

Next step is rebooting with noapic.

/dev/md1 is now a raid5-xfs on the system HD
#-------------------------------
# raid5 on hda
#-------------------------------
raiddev                 /dev/md1
raid-level              5
nr-raid-disks           3
persistent-superblock   1
chunk-size              64
parity-algorithm        left-symmetric
#
device                  /dev/hda6
raid-disk               0
device                  /dev/hda7
raid-disk               1
device                  /dev/hda8
raid-disk               2

I can still see the nfs freeze (server nfs.cluster not responding)
on both raid5 devices under 2.4.3-xfs. on the client side
syslog reports a "nfs_statfs: statfs error = 116 ".

I can still see it under 2.4.7pre8 on /dev/md0 or /dev/md1
but only after a little longer time...

Off topic: One strange thing is the checksumming function:
/var/log/messages
kernel: raid5: measuring checksumming speed
kernel:    8regs     :  1169.200 MB/sec
kernel:    32regs    :   788.000 MB/sec
kernel:    pIII_sse  :  1727.600 MB/sec
kernel:    pII_mmx   :  1924.000 MB/sec
kernel:    p5_mmx    :  2045.200 MB/sec
kernel: raid5: using function: pIII_sse (1727.600 MB/sec)

Why not using the faster p5_mmx ?

> > >4) try SMP+raid5 on local IDE HD to rule out 3ware issue
ruled out. :(

Tru
-- 
Dr Tru Huynh          | Bioinformatique Structurale
mailto:tru@xxxxxxxxxx | tel/fax +33 1 45 68 87 37/19
Institut Pasteur, 25-28 rue du Docteur Roux, 75724 Paris CEDEX 15 France


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