[mod.computers.vax] Diskquota problems

JARRELLRA@VTMATH.BITNET (Ronald A. Jarrell) (02/08/86)

There's a well known problem (at least at DEC-U.S....) with 4.N and quota
leakage.. There's a few bugs in the < 4.2 XQP, and still some in the 4.2
one...  I don't recommend running the vanilla 4.0 or 4.1 XQP's at all, DEC
has a special SPR response patch that gives you what they called the
4.1++ system (a almost 4.2 XQP), and I have unconfirmed reports of
a similar deal for 4.2 systems, that gives them the more or less
frozen (at least quite slushy) 4.3 XQP..

Course, I'm starting to get tired of testing DEC's operating systems a
piece at a time.. I'd like to not need parts of 4.2 until I want to
install the whole kit, but that's been the story of 4.N..

-Ron Jarrell
Va Tech Computing Center

BMW6957@TAMCHEM.BITNET.UUCP (01/21/87)

Had a little problem sending this first time, I'll try it again -- BW

  >On our VAX system I have noticed that the disk quota information
  >I get, whitin DISKQUOTA, whit:
  >
  >SHOW [*,*]
  >
  >disagree whit DIRECTORY ( or DIRECTORY/BY_OWNER ) totals.
  >For UIC's like [1,1] the difference is very high ( for the UIC [1,1] in
  >particular the DIRECTORY reports a total block allocated much greater
  >than the DISKQUOTA number; other UIC's report a reverse situation ).
  >
  >Our users frequently can't work due to DISKQUOTA exeeded.

The values given by DISKQUOTA include blocks allocated to the file header
in [0,0]INDEXF.SYS as well as the allocated size of the files.  DIRECTORY
shows the allocated size and size used (if /SIZE=ALL is specified), but
not the header blocks allocated.  The numbers obtained by DISKQUOTA will
never agree with those from DIRECTORY since each file and directory has
at least one header block (it may have more than one depending on file
size, contiguity options, and disk fragmentation).  Often the two values
are not even close as you observed.  However the size DISKQUOTA gives
should always be greater than that shown by DIRECTORY.  That leads to
the next problem:

The quota file can get out-of-sync with the file structure, especially
if you've had a system crash (and who hasn't had one of these at some
time?).  There are two ways to bring it back in line--use the REBUILD
command under DISKQUOTA, or use the VMS command ANALYZE/DISK/REPAIR.
ANALYZE should only be used if there is no disk activity, whereas
DISKQUOTA's REBUILD command can be done on-line.  If at all possible,
I would suggest using the ANALYZE command, as that will find and correct
many other problems such as lost files (Lost files are files that exist
on the disk, but their directory pointers have been removed.  Lost files
are still counted against the owner's quota) and files marked for delete
(Files that are found "marked for delete" were never actually deleted,
e.g. a crash occurred preventing complete deletion, they still exist
and still occupy quota).

Be absolutely certain to read the manual about ANALYZE/DISK (Verify
utility) and the possible ramifications of the /REPAIR qualifier
ESPECIALLY if you intend to do this on your system disk!  Make sure
you have a current backup.  You may also want to do a "dry run"
(i.e. ANALYZE/DISK  without the repair qualifier) just to see how
bad the file structure really is.

You may consider doing this periodically to keep the file structures
cleaned up (I do it whenever we've had a scheduled shutdown, before
I let users back on the system).

Hope that helps,
Brad Wilson