Alternative boot up strategies: internal disk
December 29, 2005
HP says that customers are moving away from parallel SCSI-attached storage for their HP 3000s. At the recent HP Technology Forum, Jim Hawkins of HP's MPE/iX IO labs said FiberChannel Storage Area Networks and shared tape libraries are becoming popular. 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 be yesterday's tools, but the modest drive inside your HP 3000 can still be very useful, even if your company has invested in the FiberChannel storage solution of the VA7100.
Moving to the VA solution has great benefits. Last year we interviewed Donna Garverick about the use of the VA7100 array with the 3000s at Long's Drug. But booting directly from a VA array — well, you'd better have an N-Class server (native FiberChannel installed) or a very expensive HP A5814A-003 Fiber/SCSI router (if you can find one) for the 900 Series servers.
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. Crossroads isn't interested in adding this functionality to its less costly array connectivity solution. Craig Lalley of EchoTech recommends the affordable Mod 20 arrays for boot capability
So if you're considering a move up to the VA arrays for your 9xx HP 3000 — or even to the XP line of HP arrays — your internal drives can remain as important as ever. Enough to even duplicate them, according to Garverick.
Garverick noted that a second bootable disc inside your 3000 can take some forethought, but it's essential in the event of an LDEV 1 failure. James Killam of HP 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."
Garverick noted:
I do have one internal disc and it is expressly for memory dumps. A second internal disc with a bootable image would be wonderful insurance. It would take some fore-thought 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!
She gave a report on Long's VA7100 maintaining 3000 uptime as promised. "We actually had a drive fail on my VA array. The array worked perfectly and switched over to the spare without a blink. Given that I’ve got two systems sharing this array, I am more than pleased with how well it worked."
Drive failures are among the most likely of hardware problems you will encounter using an HP 3000. Considering how inexpensive disk devices have become, a second internal drive in a system can make a big difference in recovery time.