Calculating stride values?
adilger at clusterfs.com
Tue Jun 5 23:23:11 UTC 2007
On Jun 05, 2007 18:47 -0400, Tod Hagan wrote:
> The mke2fs man page says
> Configure the filesystem for a RAID array with stripe-size filesystem blocks per stripe.
> So stride = size of stripe/blocksize.
> The size of a stripe is the RAID chunk size * the number of drives in the RAID.
Not really. We submitted a patch to clarify this, so the "stride=" value
is the number of blocks on a SINGLE disk. This ensures that the bitmaps
are round-robined across all disks.
> For example, take the example of six drives configured for RAID 5 with a
> chunk size of 64 and a 4K blocksize:
> 1. Parity drive included: 64*6/4 = 96
> 2. Parity drive excluded: 64*5/4 = 80
> Which is correct?
-E stride=16, based on 64k / 4k
Principal Software Engineer
Cluster File Systems, Inc.
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