I am running an Ubuntu server 10.10 machine with 24 hard disks (and two OS drives).
I am using a script to mount all the drives to their desired mountpoints. This works pretty fast, as expected, until it suddenly hangs. Usually after mounting 15 drives or something in the vicinity.
Sometimes it also mounts all drives fast, but that is rare.
Unmounting is the same thing. When I manually unmount drives it literllay takes hours to complete. For one drive I wait about 10 minutes to complete.
The mount processes is in an uninterruptable sleep mode and there is nothing in the syslog and nothing in the kernel log.
The server is a mass storage server by the hosting provider leaseweb
The drives are behind a raid controller configured in jbod mode.
My idea is maby that some sort of staggered boot/halt of the hard disks in the raid controller could cause this problem but somehow this does not really fit the behaviour.