[Info-vax] Uptime for OpenVMS

[Bob Koehler]

 On 2011-05-13 21.24, JF Mezei wrote:
> Michael Moroney wrote:
>
>> Mount Verify gets invoked if a drive goes offline when trying to do I/O
>> to it.
>
>
>
> OK, when you reboot after a crash, and the MOUNT command takes an
> eternity to complete because it does some "cleanup" of the disk, what is
> that process called ?
 
   It's rebuilding the bitmap.  You can skip that at mount with 
   /NOREBUILD, and do it at your convinience with SET VOLUME /REBUILD.

   Typically on production systems I use /NOREBUILD during boot and
   SET VOLUME/REBUILD prior to the overnight BACKUP.

   The bitmap is cached with some block pre set as allocated.  If
   the bitmap needs to be rebuilt and you delay it, there's a little bit
   of free space that's marked allocated until you do rebuild.