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October 28, 2011

Emulator query sparks private volume tip

In an example of the newest HP 3000 technology linking to one of the server's oldest, one question about a 2012 product unearthed advice about a feature introducted in 1978. Next year's HPA/3000 emulator received some upgrades to its SCSI periperals support this week, according to the product's vendor Stromasys. These improvements will make it possible to better answer a question about private MPE/iX volumes, and how well HPA/3000 can handle them.

BuiltToLastCraig Lalley, working with Stromasys on the MPE/iX aspects of HPA/3000, said he hasn't tested private volumes yet, "due to an issue with the SCSI interface. But I intend to." At the same time, a question about private volumes' use in the current era prompted some advice from Applied Technologies' Brian Edminster -- who had to miss the Reunion briefing on HPA/3000 due to pressing work to open up the new MPE open source website, MPE-OpenSource.org. (You can track updates to the project through its RSS feed, which can be viewed in Google's RSS Reader, among others.)

The first package Edminster added to site was SFTP quick-start, a bundle "which aims to make installing SFTP easier on MPE/iX systems. It is a std file which includes all the components necessary to install and configure sftp, scp, and keygen under MPE/iX, with links to instructions for the installation process."

Edminster is well-versed in the non-open-source tools for the HP 3000 as well. When Dave Powell of MMFab asked during a HPA/3000 discussion if anyone was even using private volumes on an A400 Class of server, Edminster advised that the 3000 sites where he administers or consults are employing this bedrock MPE tool -- one first introduced 34 years ago in MPE III, on the Series III.

I've always considered it a best practice to divide your disk storage up into several Private Volumes. Why?  When a non-mirrored spindle in a PV dies, it only takes that PV out with it -- allowing the rest of the machine to keep running (unless the PV is the mpe_system_volume_set, in which case you're going to be doing a system install).  If it's only one of the data volumes that goes down, the 'system' is still up, greatly facilitating recovery.

Data volume protection has always been at the heart of MPE's private volumes.

If you can't afford arrays that protect the 'system' volume-set, at least you can get something (even if it's only HP's subsystem software Mirror/iX for RAID-1) to protect the data volumes. And if you configure it properly,  RAID-1 is wicked-fast on reads, and pretty decent on writes.

Oh, and to answer your original question:  Yes, A400s can be set up this way.  At least, the ones I administer are set up this way. The drives inside the CPU chassis are set up as "system volume set," and an external mirrored array is the "data' volume.

Works great. If the system volume goes down, data isn't likely affected. If a mirrored drive fails, just swap it for a replacement. This has gotten my client near 100 percent up-time for this system, for almost 10 years now.

06:14 PM in Hidden Value, Homesteading, Web Resources | Permalink

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