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Re: Files not starting on swidth

To: linux-xfs@xxxxxxxxxxx
Subject: Re: Files not starting on swidth
From: Dave Lloyd <dlloyd@xxxxxxxxx>
Date: Fri, 09 Jun 2006 13:00:26 -0500
Sender: xfs-bounce@xxxxxxxxxxx
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The Levinson Family wrote:
We are using Suse SLES 9 SP2 (soon to upgrade to SP3) for a DB2 database
platform on an AMD64 dual cpu server.  Each server has two 256GB
partitions mounted from a clariion storage array. The clariion luns are
each a RAID 5 array with 64KByte stripe units x 4 data disks for a
256KByte stripe width.  The xfs filesystems look like

# xfs_info /dev/emcpowera1
meta-data=/mnt/db02-01           isize=256    agcount=16, agsize=4365040
blks
        =                       sectsz=512
data     =                       bsize=4096   blocks=69840576,
imaxpct=25
        =                       sunit=16     swidth=64 blks,
unwritten=1
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


I think we will adjust sunit setting on logs to match the sunit setting of the rest of the filesystem.

Those numbers indicate that they're right. Numbers reported there are in 4kb blocks, not 512 byte blocks. 4*16=64, 4*16*4=256.

The other thing to check would be to make sure that your partition
begins on stripe alignment.  parted 1.7 and up should be able to split
partitions on block sizes rather that the supid sector crap that fdisk
does.  Make sure that you're using 1.7 and up, though.

--
Dave Lloyd
Test Engineer, Exegy, Inc.
314.450.5342
dlloyd@xxxxxxxxx


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