June 15, 2011
N-Class price, storage advice points at value
While we were trolling our files for news about the HP 3000, we found a note about this year's cost of the N-Class HP 3000 servers. The ultimate HP 3000 ever built by the vendor, used as a spare parts unit or a hot backup for a production machine, sells for $3,000-$8,000 from one supplier. That's the price for a server that's got a pre-loaded version of MPE/iX, but the license is up to you to arrange. The $8,000 N-Class was listed as the most powerful (750 MhZ), sporting three processors.
On the other end of the useful 3000 power scale, the Series 927LX -- almost the smallest PA-RISC HP 3000 ever built by HP -- is still in use in the field. Chuck Trites asked this week if a DLT tape drive could be installed in this server that was designed in the early 1990s.
"This is not a problem as long as you have a free slot, or an open 28696A fast-wide card," says Jack Connor of Abtech. "I believe you need to be on MPE/iX 6.0 or 6.5 to go with a DLT8000. I'm sure a DLT4000 and probably a DLT7000 are okay." Larry Kaufman of legal firm Weltman, Weinberg and Reis reports that the 28696A IO card is easily obtained, a double-high interface device that permits the 927 to use HVD SCSI DLTs of 4000, 7000 or 8000 models.
HP 3000 managers trade this kind of configuration experience often, usually bolstered by independent support companies like Gilles Schipper's GSA. Schipper adds that some DLT4000s have a Single-Ended SCSI interface if that 927 doesn't have a spare full-height slot.
You might miss one point of this set of exchanges. At one end there's a 20-year-old server still working in a production setting. At the other end, the most powerful 3000s sold by HP are now less than $10,000, at least in a spare-parts or hot DR offering with your own licenses. There's value available for a server HP hasn't built in more than seven years, if you know where to ask for help.Trites, who runs a consultancy that serves 3000 managers and sites, created a tape with a DLT4000. "What I need to do is restore the databases on the tape to my system for a project. I only have a DDS drive, and don't know if it's worth trying to install a DLT drive or not." Mostly, that would depend on the price of the DLT SE-SCSI w
Other 3000 IO advice is being offered on balancing file allocations by duplicating a DISC class in SYSGEN. "I want to put an 18GB drive on LDEV 1 and a 9GB on LDEV 2: DISC twice on LDEV 1 would seem to be good to do this," says John Pitman. "I tried to do this in SYSGEN, but it said it was already there."
That used to be a good technique in the pre-MPE/iX and MPE/XL days. But it’s not necessary any longer. MPE will naturally choose whichever disc has the most free space for its file disc space allocation.
And there is also a special allowance for LDEV 1 to ensure it does not prematurely fill up. You can control some aspects of disc utilization via the permanent and transient percentages that can be manipulated via VOLUTIL.
Craig Lalley of EchoTech notes that the VOLUTIL commands are
ALTERVOL MPEXL_SYSTEM_VOLUME_SET:MEMBER Perm# Trans#
HP's own Jim Hawkins, a longtime engineer in the IO labs for the 3000, offered his insights on how MPE/iX uses its algorithm to balance the allocations.
I poked around in this code as part of the "Large Disk" patch set. The algorithm is based upon percentage full -- that is, we pick the disk in the set with lowest percent full. Note though this does have a disadvantage that if your volumes are very different sizes as you may bottleneck or serialize lots of IO to the larger disks.
MPE does do better when disks are matched in size. Also, the original algorithms were designed when 4 GB was a really big disk, so were granular to 1/100. With one of the Large Disk patches, I think I made that 1/10000 -- otherwise you'd have to add 3GB of files to a 300GB disk before you'd move to the next volume.
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