Thanks that helps. Now that I know I have the right sunit and swidth I have a
performace related question.
If I do a dd on the raw device or to the lun directy I get speeds of around
As soon as I add xfs on top of the lun my speeds go to around 150 MBytes/sec.
This is for a single stream write using various block sizes on a 2 Gbit/sec
fiber channel card.
Is this overhead more or less what you would expect from xfs? Or is there some
tunning I need to do?
From: Nathan Scott <nscott@xxxxxxxxxx>
Date: Tue, 12 Jun 2007 10:34:04
To:"Salmon, Rene" <Rene.Salmon@xxxxxx>
Subject: Re: sunit not working
On Mon, 2007-06-11 at 18:55 -0500, Salmon, Rene wrote:
> As you can see the sunit gets set to 64 upon creation and not 512 like I
> asked. Also if it try to give it some mount options it does the same
> sgi210a:~ # mount -o sunit=512,swidth=5120 /dev/mapper/mpath9 /mnt/
Its being reported in units of filesystem blocks, and its specified
in 512 byte units. Pretty dopey, but thats why its different.
> sgi210a:~ # xfs_info /mnt/
> meta-data=/dev/mapper/mpath9 isize=256 agcount=32,
> agsize=56652352 blks
> = sectsz=512 attr=0
> data = bsize=4096 blocks=1812874752,
> = sunit=64 swidth=640 blks,
> naming =version 2 bsize=4096
> log =internal bsize=4096 blocks=32768, version=1
> = sectsz=512 sunit=0 blks
> realtime =none extsz=65536 blocks=0, rtextents=0
> sgi210a:~ #
$ gdb -q
(gdb) p 512 * 512
$1 = 262144
(gdb) p 64 * 4096
$2 = 262144
(thats 262144 bytes, of course)
> Last I tried to subscribe to the list by sending email to
> ecartis@xxxxxxxxxxx a couple of times but was unsuccessful should I send
> email elsewhere to subscribe?
Its a frikkin' lottery. :) Keep trying and keep whining is how I ended
up getting back on (whining on IRC on #xfs helps too).