FiberChannel Storage Area Networks and shared tape libraries became popular in the years after HP stopped making its MPE/iX hardware. The HP 3000 supports SAN from the XP series of RAID devices to the VA7100 disk arrays. But how much should you rely on a RAID or SAN device? Internal storage devices might seem to be yesterday's tools, but the modest drive inside an HP 3000 can still be very useful — even if a company has invested in the FiberChannel storage solution of the VA7100.
Moving to the VA solution has great benefits, as reported in a story about using a VA7100 array with the 3000s. But booting directly from a VA array — well, you'll need an N-Class server (native FiberChannel installed) or a very expensive HP A5814A-003 Fiber/SCSI router (if you can find such a thing) to employ VA in the 9x9s.
The Crossroads SA-40 Fiber/SCSI switch will link a VA array to 9xx 3000s. It just won't let you boot your MPE/iX system from any of its drives. Craig Lalley of EchoTech recommends the affordable Mod 20 arrays for boot capability.
Internal drives remain as important as the VA arrays for a Series 9xx HP 3000, or even to the XP line of HP arrays. Even important enough to even duplicate them.
A second bootable disk inside your 3000 can take some forethought, but can be essential to smooth recovery of an LDEV 1 failure. James Killam of HP once reported to the 3000 mailing list, "Keeping a bootable image of MPE on one of the internal drives... saved me once at 2 AM when we lost total connectivity to the XP array the system was attached to and we had some serious troubleshooting to do."
Donna Hofmeister, former OpenMPE board member, has noted:
I did one internal disc and it was expressly for memory dumps. A second internal disc with a bootable image would be wonderful insurance. It would take some planning to be able to manage it all, but there’s no reason why you can’t have two bootable discs. I’ll point out the obvious: if LDEV 1 is internal, and you have a multi-disc system volume, and the remaining system storage is on a disc array — uh, what’s the point? If LDEV 1 fails, you’re toast.
Hofmeister said she's had a drive fail on a VA array. "That array worked perfectly and switched over to the spare without a blink. Given that I had two systems sharing this array, I was more than pleased with how well it worked."
Drive failures are among the most likely of hardware problems using HP's 3000 devices. A second internal drive in a system can make a big difference in recovery time. The other way around drive failures is to make your way onto emulated PA-RISC systems from Stromasys.