I restored the degraded RAID-1 (mirror) arrays of the system disk except for /dev/md3 (/usr partition), which has the bad spo on /dev/sdb and is therefore no longer redundant.
I have made a backup of the crontabs that are set up on adaql1: /adaql3/work2/adaql1/crontabs. This would at least allow the halog to come back quickly. I don't know what else is running there, though, which would be critical for DAQ. Bob or another DAQ expert should prepare adaql3 as a backup machine just in case.
A copy of this log entry has been emailed to: rom, riordan