Troubleshooting
Common SCSI Bus Problems 55
SCSI Bus Symptom Probable Cause Solution
SCSI Bus hangs, SCSI
Bus excessive retries,
and/or drives drop
offline.
Faulty connectivity.
Faulty I/O Interface card.
Re-check the cables to the I/O
Interface card and host adapter.
Depending on how many
subsystem are connected on the
SCSI bus, you will need to
perform some fault isolation.
If all the drives on one bus are
offline, start with the subsystem
furthermost out on the chain.
Disconnect the data cable. If the
remaining drives return to a
normal state it indicates that
the isolated subsystem has the
faulty component.
If this does not return the
remaining drives to a normal
state, continue removing each
data cable on that bus until the
first subsystem is the remaining
subsystem.
If you had to remove all the data
cables up to the first subsystem
and the problem is still not
resolved, this could indicate
that the I/O Interface card in
the first subsystem is the
suspect faulty card. Use one of
the cards from the previous
subsystems or a “new” known
good card. This should return
the subsystem bus to a normal
condition.
Note: A return to a normal
condition is indicated by the
drives coming back online.
After the faulty card is
replaced, begin re-connecting
the data cables on the
remaining I/O Interface cards
noting the bus remains in a
normal state.