Raid 5 on Fedora 4 working with SATA ?

[Terry Barnaby <terry1 beam ltd uk>]

Hi,

I have just set up a Raid 5 disk array using 4 SATA disks on Fedora 4.
To test the setup I unplugged the SATA cable from one of the disk drives.
I was expected the system to carry on with messages from the Raid system
indicating that there was a disk drive down.

However the Raid 5 partition became completely inaccessable after un-plugging
the drive. The kernel reported disk errors but there was no error messages
from the Raid system and "mdadm -Q --detail /dev/md2" reported that there
was no problems with the Raid array.

When I rebooted the system (needed a reset) the Raid system reported that
one disk was down and the partition became readable again.

It appears that the default configuration of the Raid 5 system does not
handle a complete drive failier during up-time. I presume it may respond to
disk errors from a disk drive that is connected but once disconnected the
Raid system appears to ignore errors.

Is there a configuration option to allow the Raid system to respond to
a completely broken drive or cable ?

Terry