Forgetable SCSI??

[Jeff Giacobbe]

First of all, thanks to those who responded to my question on a 4/330
server supporting SLC clients under 4.0.3 !

Another similar problem has reared it's ugly head.  Occasionally, our
server 'forgets' that it has an external SCSI disk!  Let me explain:

We're running a Sun 4/330 server (OS 4.0.3) with an internal CDC 9720 boot
drive, and an external Sun 669 meg SCSI drive w/150meg tape.  The server
is supporting four diskless 3/80's and ten diskless SLC's (hmmm, sounds
familiar :-) )

Every once in a while (three times so far in two months) the server
decides to ignore the external drive.  Everything will be working fine -
all ten SLC's are supported on the external drive - and then bang, the
server drops the external drive completely, and hanging the clients.
Doing a 'df' shows the first 3 partitions from the internal boot drive and
then hangs at the point where it should print out the first partition of
the external drive:

Ex: 

# df

/dev/xd0a         ..........
/dev/xd0g         ..........
/dev/xd0e         ..........


and then it hangs, cntrl c or z won't break out of the df process.  A
reboot seems to be the only thing that gets things going again!  HELP!
Any clues/ideas/help/advice ??