PJS@naif.JPL.NASA.GOV (Peter Scott) (05/17/88)
I'd be interested in hearing from anyone who has been using Executive Software's Diskeeper Continuous Defragmenter, particularly any problems. Peter Scott (pjs%grouch@jpl-mil.jpl.nasa.gov)
ZWARTS@HGRRUG51.BITNET (05/24/88)
> I'd be interested in hearing from anyone who has been using Executive > Software's Diskeeper Continuous Defragmenter, particularly any problems. We have had DISKEEPER version 2.0 for a one month trial period. DISKEEPER claims to be able to defragment disks, even system disks, in a running system, even in a Vax Cluster environment. Indeed, DISKEEPER succeeded to defragment our disks to a large extent. We did not discover any fatal data corruption. The human interface in nice and simple and, the output, in particular from the disk-analyzer that goes with it, is very clear and instructive. So far the advantages. The disadvantages: First the documentation mentions that you may not run ANALYSE/DISK when DISKEEPER is running. It mentions another, third party, software product, which may not run simultaneously with DISKEEPER. This made us feel unhappy. Second, on all disks for which we ran DISKEEPER, the ANALYZE/DISK utility reported after a few days the following problem "Block uncorrectly marked allocated" and a list of sometimes several hundreds of blocks followed. This could be repaired with ANALYZE/DISK/REPAIR and we discovered no data-corruption, but again, it made us feel unhappy. We would like a utility that does not need continuous attention. Third, DISKEEPER claims to defragment systems disks. However, this means that it moves only the "save" files. It does not move e.g. SYSDUMP.DMP, PAGEFILE.SYS, SWAPFILE.SYS, nor any installed image or open file (I can understand why). A large fraction of the file space on our system disk belonged to one of these categories, so the defragmentation was only partly successfull. (It might be that if you do a BACKUP/RESTORE operation before starting DISKEEPER, the defragmentation is kept on a better level than in our case, which probably started from the worst case.) Finally, DISKEEPER is protected by checks of SID registers, etc. (There has been a discussion on this type of protection in INFO-VAX some time ago.) Although, it was said that we could run it on a backup system in cases of problems with our main Vax, we were not able to make it run on a different Vax processor. A more general remark on defragmentation. Although DISKEEPER succeeded to defragment our disks rather well, we did not notice a dramatic performance improvement. (We are not allowed to mention results of bench marks without written permission.) Also the DISKEEPER documentation mentions improvements of 20% to 30% in cases of badly fragmented disks. I think most users will not notice such an improvement, except in already over-loaded systems. It seems it is usefull only in cases where disk space and CPU time is very scarce, to delay the necessity to buy more disk space. This made us wonder whether defragmentation is the right way to go for our investment. If we use the money otherwise paid for DISKEEPER for extra disk capacity, and we do a BACKUP/RESTORE operation a few times a year, we think we spend our money better. This might be different in your environment, of course. Very much depends on life times of files. F. Zwarts Phone: (+31)50-633619 Kernfysisch Versneller Instituut Bitnet/Earn: ZWARTS@HGRRUG51 Zernikelaan 25 Surfnet: KVIANA::ZWARTS 9747 AA Groningen Telefax: (+31)50-634003 The Netherlands Telex: 53410 rugro nl
ZWARTS%HGRRUG51.BITNET%CUNYVM.CUNY.EDU%KL.SRI.COM%lbl%sfsu1.hepnet@LBL.GOV (05/29/88)
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Date: Tue, 24 May 88 10:46 N
From: <ZWARTS%HGRRUG51.BITNET@CUNYVM.CUNY.EDU>
Subject: Re: DISKEEPER
To: info-vax@kl.sri.com
X-Original-To: info-vax@kl.sri.com
> I'd be interested in hearing from anyone who has been using Executive
> Software's Diskeeper Continuous Defragmenter, particularly any problems.
We have had DISKEEPER version 2.0 for a one month trial period. DISKEEPER
claims to be able to defragment disks, even system disks, in a running system,
even in a Vax Cluster environment.
Indeed, DISKEEPER succeeded to defragment our disks to a large extent. We did
not discover any fatal data corruption. The human interface in nice and simple
and, the output, in particular from the disk-analyzer that goes with it, is
very clear and instructive. So far the advantages.
The disadvantages: First the documentation mentions that you may not run
ANALYSE/DISK when DISKEEPER is running. It mentions another, third party,
software product, which may not run simultaneously with DISKEEPER. This made us
feel unhappy. Second, on all disks for which we ran DISKEEPER, the ANALYZE/DISK
utility reported after a few days the following problem "Block uncorrectly
marked allocated" and a list of sometimes several hundreds of blocks followed.
This could be repaired with ANALYZE/DISK/REPAIR and we discovered no
data-corruption, but again, it made us feel unhappy. We would like a utility
that does not need continuous attention. Third, DISKEEPER claims to defragment
systems disks. However, this means that it moves only the "save" files. It does
not move e.g. SYSDUMP.DMP, PAGEFILE.SYS, SWAPFILE.SYS, nor any installed image
or open file (I can understand why). A large fraction of the file space on our
system disk belonged to one of these categories, so the defragmentation was
only partly successfull. (It might be that if you do a BACKUP/RESTORE operation
before starting DISKEEPER, the defragmentation is kept on a better level than
in our case, which probably started from the worst case.) Finally, DISKEEPER is
protected by checks of SID registers, etc. (There has been a discussion on this
type of protection in INFO-VAX some time ago.) Although, it was said that we
could run it on a backup system in cases of problems with our main Vax, we were
not able to make it run on a different Vax processor.
A more general remark on defragmentation. Although DISKEEPER succeeded to
defragment our disks rather well, we did not notice a dramatic performance
improvement. (We are not allowed to mention results of bench marks without
written permission.) Also the DISKEEPER documentation mentions improvements of
20% to 30% in cases of badly fragmented disks. I think most users will not
notice such an improvement, except in already over-loaded systems. It seems it
is usefull only in cases where disk space and CPU time is very scarce, to delay
the necessity to buy more disk space. This made us wonder whether
defragmentation is the right way to go for our investment. If we use the money
otherwise paid for DISKEEPER for extra disk capacity, and we do a
BACKUP/RESTORE operation a few times a year, we think we spend our money
better. This might be different in your environment, of course. Very much
depends on life times of files.
F. Zwarts Phone: (+31)50-633619
Kernfysisch Versneller Instituut Bitnet/Earn: ZWARTS@HGRRUG51
Zernikelaan 25 Surfnet: KVIANA::ZWARTS
9747 AA Groningen Telefax: (+31)50-634003
The Netherlands Telex: 53410 rugro nl