Proper alignment between disk HW blocks, mdadm strides, and ext[23] blocks
Chris Worley
worleys at gmail.com
Sat Nov 10 02:11:50 UTC 2007
How do you measure/gauge/assure proper alignment?
The physical disk has a block structure. What is it or how do you
find it? I'm guessing it's best to not partition disks in order to
assure that whatever it's block read/write is isn't bisected by the
partition.
Then, mdadm has some block structure. The "-c" ("chunk") is in
"kibibytes" (feed the dog kibbles?), with a default of 64. Not a clue
what they're trying to do.
Finally, mkfs.ext[23] has a "stride", which is defined as a "stripe
size" in the man page (and I thought all your stripes added together
are a "stride"), as well as a block size.
It's important to make sure these all align properly, but their definitions do.
Could somebody please clarify... with an example?
Thanks,
Chris
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