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Q: Partition offset setting vs displaying

bobthesungeek76036Mar 22 2012 — edited Mar 22 2012
My customer has RHEL systems connected to CLARiiON storage. Per EMC recommendations, they have modified the offset of the partition start to 128 to align with the backend disk blocks. The default offset is 63 if I remember correctly. However, when I look at two different LUNs (one with the 128 offset and one with the default) I get different numbers:

</pre>$ sudo powermt display dev=all | grep Pseudo | egrep 'poweri|powerj' | cut -d= -f2 | awk '{ print "sudo fdisk -l -u /dev/"$1 }' | sh

Disk /dev/emcpoweri: 126.7 GB, 126701535232 bytes
255 heads, 63 sectors/track, 15403 cylinders, total 247463936 sectors
Units = sectors of 1 * 512 = 512 bytes

Device Boot Start End Blocks Id System
/dev/emcpoweri1 128 247449194 123724533+ 83 Linux

Disk /dev/emcpowerj: 134.2 GB, 134217728000 bytes
64 heads, 32 sectors/track, 128000 cylinders, total 262144000 sectors
Units = sectors of 1 * 512 = 512 bytes

Device Boot Start End Blocks Id System
/dev/emcpowerj1 32 262143999 131071984 83 Linux
$</pre>


As you can see the offset for emcpoweri shows the 128 offset that was set in fdisk when it was created. However, when emcpowerj was created it was left to default which should be 63 but it displays 32. So which is it? Is the default 32 but the default for the "b" advanced option 63? Or is fdisk confused?


(Are we not able it inject HTML into posts anymore? My tags are not being recognized)

Edited by: bobthesungeek76036 on Mar 22, 2012 8:06 AM
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