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- Path: sparky!uunet!mcsun!sunic!psinntp!psinntp!npri6!richard
- From: richard@npri6.npri.com (Richard Head)
- Newsgroups: comp.os.vms
- Subject: Re: DEC File Optimizer for VMS
- Message-ID: <6135@npri6.npri.com>
- Date: 6 Sep 92 15:00:36 GMT
- References: <1992Sep2.165101.1869@bvc.edu> <1992Sep3.075945.1@hiramb.bitnet>
- Distribution: world
- Organization: NPRI, Alexandria VA
- Lines: 92
-
- williamsca@hiramb.bitnet (Curtis Williams) writes:
- #
- #>We have installed DFG010 on our 6510 and Workstation. Every time I have tried
- #>to run it on the workstation the drive where news items are located there are
- #>several things that happen. First, DFG goes through a file evaluation phase
- #>which takes a while because there are so many files. Next, it goes the a file
- #>pre-processing phase which I have seen take 10 hours or more. At this point,it
- #>goes into an RWAST state and I never see it work again. I have also tried to
- #>run it on the 6510 one time and it went into RWAST there as well.
- #
- #>Has anyone else had similar experiences?
-
-
- The following is a re-post of my DEC File Optimizer experiences:
-
-
-
- * * * * * * * * * *
-
-
- Newsgroups: comp.os.vms
- Subject: Re: DEC DFO - What's the "full" story?
- Message-ID: <5864@npri6.npri.com>
- Date: 13 Jul 92 01:34:13 GMT
- Distribution: world
- Organization: NPRI, Alexandria VA
- Lines: 65
-
-
- I have experienced a number of caveats with DEC File Optimizer ("DFO"):
-
- ** DFO has the capability of optionally reading in user created "options"
- files that specify one or more of the following:
-
- o Files/Directories to be excluded from movement/defragmentation
-
- o Files/Directories to be considered frequently accessed, therefore
- moved to a more optimal location on the disk for more effecient
- disk access.
-
- o Files/Directories to be considered dormant, therefore moved to a
- location on the disk (I think) would be considered less optimal,
- since it isn't accessed much anyway.
-
-
- There are at least 3 caveats with these options files:
-
- 1) You must specify the disk device name in the options file. This is absurd,
- since the defragmentation process only works on 1 disk. Thus, you can't
- specify [...]*.*;*, you must specify <DISKNAME>:[...]*.*;*.
-
-
- 2) There is the potential for abuse with the options file here. Since it
- allows wildcarding in the filespec, an options file may specify thousands,
- or even hundreds of thousands of files to be excluded, considered frequent,
- or considered dormant.
-
- From what I could ascertain, DFO wants to read in the file header for each
- file it can process from the options file. When your wild-carded file specs
- included thousands of files, the working set of the defragmenter process
- must extend to read in all of these headers. I pressed the envelope on my
- system and a DFO process increased to over 10,000 pages.
-
- Since the working set extent of the DFO engine process cannot be specified
- on any command line /any startup file, the only resolution I could find at
- the time was to increase the sysgen parameter PQL_MWSEXTENT (to 12000 on my
- system). Since extent size rarely creates a problem, this isn't serious.
-
- 3) The more stuff in the options file, the longer it will take. Unless you
- *really* want something to be considered frequent or dormant, don't use it.
- IMHO, RAXCO's PerfectDisk approach is more sophisticated. They use volume
- expiration to determine how frequently a file is accessed, and will place
- the file based upon user-supplied information on what the "warehouse" and
- "frequent" dates should be. None of this reading file headers into memory
- baloney. (I think).
-
-
- ** Using BYPASS. I don't recall about PerfectDisk, but DFO uses the BYPASS
- privilege with a vengeance. Normally, this isn't a problem. If you have
- security auditing for FILE_ACCESS=BYPASS enabled, stand by for a potential
- audit log meltdown. Even if only a few files have their file protection
- set so that SYSTEM doesn't have Delete access, it seems like DFO wants to
- work on a file over and over and over again. This will generate a *lot* of
- audit messages. Either disable BYPASS auditing, or ensure all (most) files
- on the disk have S:RWED access.
-
-
- After I figured this stuff out, it works ok ;-)
-
- --
- richard@npri6.npri.com <Richard Head>
- I've fallen and I can't reach my beer!
-