[Info-vax] Defrag Fails on a Large Disk

[Louis Krupp]

On Mon, 26 Feb 2018 18:30:14 -0800 (PST), richard.l.dyson at gmail.com
wrote:

>Hi,
>
>I have an IA64 rx2660 running OpenVMS v8.1-1H1.  Can't upgrade to anything else,
>off support.  I have a single spindle disk, 600 GB SAS.  Every time I run Defrag (v3.0) I get this error:
>
>%SYSTEM-W-ACCVIO, access violation, reason mask=!XB, virtual address=!XH, PC=!XH, PS=!XL
>
<snip>
>
>Any suggestions to try?  Or other info needed?

It's been years since I've done any VMS system administration, but for
what it's worth, here's my reaction:

There's a bug in the defragger (or somewhere else in OpenVMS). The
error message isn't even properly formatted.

There might be a problem with your disk (bad links, bad sectors, maybe
both).

My advice?

If you haven't backed up your disk, do it now.

Run ANALYZE/DISK. If there's a problem, ANALYZE/DISK/REPAIR might fix
it, and then defragmentation might work.

If it doesn't, and if you have an up-to-date backup (or two), restore
to a clean disk. That should take care of the fragmentation for a
while.

There's a chance that defragmentation of a badly fragmented disk
exposes a bug.  Frequent defragmentation might go smoothly. You never
know.

Good luck.

Louis