From mboxrd@z Thu Jan  1 00:00:00 1970
From: Justin Piszcz <jpiszcz@lucidpixels.com>
Subject: 2.6.20: stripe_cache_size goes boom with 32mb
Date: Fri, 23 Feb 2007 06:41:51 -0500 (EST)
Message-ID: <Pine.LNX.4.64.0702230640430.3781@p34.internal.lan>
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Each of these are averaged over three runs with 6 SATA disks in a SW RAID 
5 configuration:

(dd if=/dev/zero of=file_1 bs=1M count=2000)

128k_stripe: 69.2MB/s
256k_stripe: 105.3MB/s
512k_stripe: 142.0MB/s
1024k_stripe: 144.6MB/s
2048k_stripe: 208.3MB/s
4096k_stripe: 223.6MB/s
8192k_stripe: 226.0MB/s
16384k_stripe: 215.0MB/s

When I tried a 32768k stripe, this happened:
p34:~# echo 32768 > /sys/block/md4/md/stripe_cache_size
Connection to p34 closed

I was able to Alt-SysRQ+b but I could not access the console/X/etc, it 
appeared to be frozen.

FYI.

Justin.