Date: Thu, 2 Mar 2000 14:21:14 -0800
From: Brian Pomerantz <[EMAIL PROTECTED]>
Is there a way to tell ext2 to use a larger block size than 4KB
without major overhauls to the source code? I would like to at least
be able to use an 8KB block size to match the size of the pages on the
Alpha. I was hoping to match the stripe size of my RAID 5 system to
avoid any read-modify-write situations when writing to the RAID
device. The smallest stripe size I can make is 8KB, which may give me
a decent performance if I have an 8KB block size.
Only very small changes would be needed to have ext2 support 8k blocks
on an Alpha. Howeever, such a filesystem wouldn't be currently
supported on am i386 machine. It's simply changing some check codes in
e2fsprogs and in the ext2 kernel code.
Also, I saw (and used) the "-R stride=" option to align the stride *
block-size with my RAID stripe. What exactly does this option buy me?
Will the file system layer wait to write the blocks until it has gotten
the whole of stride * block-size in in-memory data? The only way to
get the maximum write performance out of a RAID 5 setup is to make
sure you are not getting into a read-modify-write situation. Latency
isn't necessarily an issue for me, just raw write performance.
The main thing the stride parameter does is to make sure that the block
and inode bitmaps are scattered across RAID disks. This evens out the
load on the disks a bit.
- Ted
