[Info-vax] 8.4 freespace-drift problem?

[Michael Moroney]

JF Mezei <jfmezei.spamnot at vaxination.ca> writes:

>Question:

>does SET VOLUME/REBUID perform the
>	same, subset or superset of ANA/DISK/REPAR ?

>Do both essentially freeze the disk while the operation goes on ? Or is
>the apparent freezing just a performance issue as disk operations
>continue normally ? Does SET VOL/REBUILD and ANA/DISK/REPAIR behave the
>same on that level ?

Both take out the volume allocation lock (forget its correct name) and
doing so blocks file creation, deletion and extension.  Other disk IO
is not blocked.

Note that ANALYZE/DISK/NOREPAIR does *not* take out this lock, so you
frequently see strange results when doing this on a busy volume, as the
picture of the volume changes on the fly.

ANA/DISK/REPAIR does more than SET VOL/REBUILD, such things as looking for
files not in a directory or directory entries not pointing to a valid 
file.