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July 07, 2017

Fine-tune Friday: opening disk, adding HASS

I need contiguous file space for my XM log file. How do I get this?

Many operations on the HP 3000 require contiguous disk space. Other files also require contiguous space; for example, consider the contiguous disk space on LDEV 1 required for an OS update. If you do not have one of the several third-party products that will create contiguous disk space on a drive, you may still be able to get enough free space by using CONTIGVOL.

However, occasionally, CONTIGVOL will stop with a message of “*Warning: Contigvol - Inverse Extent Table Full, Internal resource limit.” What can you do? Run it again. HP’s Goetz Neumann reported the message "is a warning that an internal table has filled up. It appears CONTIGVOL only handles looking at 40,000 extents at a time. You can run CONTIGVOL multiple times if the first run does not condense the free space enough because of this limitation.

I am adding two drives to a HASS (Jamaica) enclosure that already has several drives. How do I do this?

Gilles Schipper, Lars Appel and Chris Bartram reply:

First, a note of caution. If you dynamically add disk drives to, say, your MPEXL_SYSTEM_VOLUME_SET, you could find yourself in a pickle if you subsequently perform a START RECOVERY by accident or design. So while you can add drives dynamically as a convenience, it is a good idea to schedule a SHUTDOWN, START NORECOVERY as soon as possible to “fix” the new drives in your base configuration.

You do not even have to take down the system to add the drives to an HASS enclosure. The following steps will do the job.

• Set proper SCSI IDs. Make sure the SCSI addresses of the HASS enclosures are what you believe them to be. Do not make any assumptions. You need to set the SCSI address dip switches properly and ensure they are unique for the controller they are attached to. You will probably need a little flashlight to check the settings.

• Plug in the new drives.

• Use IOCONFIG to add the appropriate paths and device IDs. Note that the ldevs cannot be in use by, for example, vt or telnet sessions. So, you may still need to do this “off hours.”

• Use VOLUTIL to NEWVOL or NEWSET. For example, 

>newvol mpexl_system_volume_set:member99 99 100 100 

(This example is for LDEV 99 — the “99” in member99 does not need to correspond to the LDEV number, it only needs to be unique for that volume set.)

It might be a good idea to first run the drives in a NEWSET for a while, exercising them a little. You could also use that extra volume set to exercise seldom used VOLUTIL commands or NEWACCT options like ONVS/HOMEVS. Finally, SCRATCHVOL them and add them to the desired volume set.

09:55 PM in Hidden Value, Homesteading | Permalink

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