MDADM: Debian Wheezy vs Squeeze...

A few days ago I had to rebuild my storage server due to an hardware upgrade (I created one main storage server with a xeon E5 and sixteen 4 TB disks so the Acer H340 became the secundary storage server) so I re-installed the operating system and create a new 4 disks raid 5 with four 3 TB Seagate disks...

I left all my Wheezy install disks at work so I used the "old-stable" Squeeze disks (64 bit of course!)...
The result was amazing compared to the Wheezy previous installation! The raid rebuild process was three times faster! On Wheezy the rebuild process was done at 38-40 MByte/sec but on Squeeze at 102 MByte/sec!

These were the conditions (the same I always use!):

• /proc/sys/dev/raid/speed_limit_min = 50000
• /proc/sys/dev/raid/speed_limit_max = 200000
• /sys/block/md0/md/stripe_cache_size = 8192
• NCQ disabled on all disks
• raid created on aligned partitions (with parted)

I can only think about a software regression!
More tests to come!