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June 20, 2016

Solitary backup tape spurs fresh MPE plea

When a 3000 site did its backups recently, the process did more than protect data on the business server. The procedure made a case for moving off the original HP 3000 hardware. Or keeping a couple of key tapes well protected.

Solitary ManLast week Greg Terterian left a request on 3000-L for help with a client. "They had problems with their disk storage and were going to do a reload," he said. "However, when backing up they were using the same tape over and over for the past three years."

As you might imagine, a solitary piece of backup media used repeatedly developed a problem over those years. The tape's no good. "Now they want to know if they can get or purchase, or if someone will be willing to donate, the MPE/iX 7.5 operating system."

There used to be a way to request new media for MPE/iX from HP, but that's a part of the 3000's legacy by now. Client Systems could once handle upgrade requests for part of the MPE/iX subsystem, but they were not answering calls at the start of 2016. The last HP 3000 distributor, Client Systems' domain is now parked.

Whether Terterian's client gets replacement MPE/iX files isn't the point of the story. (If you're donating, his email address is here.) The lesson is that a single backup tape is a solution that HP's hardware can let you stumble into, because restoring from tape is the norm for non-virtualized MPE/iX systems. If you're using an emulated 3000, however, your backup and bootup happens using disk files off images stored on stock PC hard drives. You could even back up to a cloud service like CrashPlan or Carbonite, if your MPE server runs off such Intel PC hardware.

A solitary tape for backups is better than no backup at all, but holding onto a CSLT tape with the operating system on it is a bedrock practice. Best of all would be to eliminate the need for tape backups by using disk images. Charon does this as its way of creating MPE/iX volumes, including LDEV 1.

A donation of a tape with only MPE/iX on it would have to include no company data on it. A CSLT is a crucial component of the HP-based 3000 experience. You can't recover a 3000 only from a nightly backup. 

"If your nightly backup is using SYSGEN to output to tape," says 3k Associates' Chris Bartram, "plus you have it set up appropriately, then you could recover from a nightly backup, but that's not common. Normally you should maintain a separate CSLT (actually two copies, to be safe) made after you have done any system configuration changes."

It's key, this CSLT, to homesteading. Overlooking the CSLT is so common that even some admin pros have done it from time to time. For one such pro, an A-Class 3000 was rebuilt and had its apps consolidated. But the rebuilt system didn't have its CSLT freshened, which was discovered when the boot volume failed. 

We lost LDEV1 in the 'system' volume-set. The apps and databases are fine, but I'd neglected to make a fresh CSLT once the rebuild/configure/setup was complete. Fortunately, all the data volumes are protected with Mirror/iX -- but rebuilding the system volume accounts, network config, administration jobs and so on has been a pain.

An honest mistake like this is not one you need to make yourself. Even if, as another 3000 consultant notes, your shop has gone into Frugal Mode while it makes in-house migration moves. You have the right to be wrong in Frugal Mode. But you really don't want that right, unless you've got plenty of extra time. 

09:12 PM in Migration | Permalink

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