I tried to run 2.5.30 on a smp machine that use raid-1 and raid-0.
The RAIDs are autodetected.  The bootup fsck complained
that it couldn't find a valid superblock on /dev/md/1, which scared me
a bit.  But there is no problem with the device - mount
does not complain and mounts the fs (ext2) just fine.

The 2.5.30-kernel is patched for a max BIO size of 4k, so there
won't be trouble with BIOs crossing stripe boundaries.

2.5.7 have no problem with the RAIDs.

Helge Hafting