[Info-vax] Need help mounting shadow set

[Richard B. Gilbert]

Tom Adams wrote:
> On Oct 7, 8:14 am, "R.A.Omond" <Roy.Om... at BlueBubble.UK.Com> wrote:
>> Tom Adams wrote:
>>
>>> [...snip...]
>>> I kept my "bad" disk in the shadow set.  It is currently showing no
>>> errors.  I think the "bad" disk is only a problem when a bad block
>>> gets located in a trailing block of a file where the sun don't shine.
>>> When that happens, it logs an error when I put it in the shadowset or
>>> when I run ANAL/DISK/SHAD.  Or, so I have been told here.  I guess its
>>> a bug in the shadowing software that does not handle the trailing
>>> blocks consistently.
>> OK, since you've kept your "bad" disk, you might consider re-formatting
>> it (and, no, that's not a bug in the shadowing software).
>>
>> Check out Hoff's recent addition to the World of Knowledge at:
>>
>> http://labs.hoffmanlabs.com/node/1414
>>
>> So, say your "bad" disk is DKB100:
>>
>> 1) Dismount it from your shadowset
>>
>> 2) $ mcr sys$etc:rztools_alpha
>>     RZTools> dkb100: /format
>>
>> This will do a low-level format of your disk, and add any bad blocks
>> found to the bad block list, giving you a "fresh" disk.
> 
> I tried that before I bought the "new" disk.  It was suggested on an
> earlier thread during earlier rounds of my battle with this disk.
> Did not do any good.  Still got bad blocks when I recomposed the
> shadowset.
> 
> Do we know that that would even work in theory?  Does shadowing even
> use that bad block list?
> 
>> How long it lasts before new bad blocks are found is another question
>> for another time ;-)
> 
> 
> 

Your best bet might be to spend some bucks to buy THREE identical disks. 
  Use two to make a RAID-1 set and the other as a spare.  If you expect 
to have to support this configuration for many years you might want to 
purchase more spares.  A disk drive might last five years in service.

A few months ago, I saw a post from someone who was supporting a system 
about twenty years old and could no longer find identical replacements 
for his disks.  Whatever hardware you buy today will be replaced with a 
newer model in six to eighteen months.  If you need, or can live with, 
obsolete equipment just stock up.  Be prepared to replace disk drives, 
fans, and anything else with moving parts.