Is it bad to run a disk defrag while running Boinc? I have my Norton setup to do an automatic scan of my 2 hard drive and then do a DF if either one is more then 5% fragged. Can this mess up Boinc or will it just slow doing the DF process? With my craptastic PC I need all the Boinc time I can get, dont even like to shut it off overnight (running 3 projects).

http://www.boincstats.com/signature/user_638784_project-1.gif

Is it bad to run a disk defrag while running Boinc? I have my Norton setup to do an automatic scan of my 2 hard drive and then do a DF if either one is more then 5% fragged. Can this mess up Boinc or will it just slow doing the DF process? With my craptastic PC I need all the Boinc time I can get, dont even like to shut it off overnight (running 3 projects).

Defraging could cause problem if a file Boinc is trying to write to is locked by Norton to move it.

BTW Unless your drive are still in FAT32 format (pre-WinXP), defragmenting them is of borderline usefulness and mostly just adds to the wear and tear on the drive.

BTW 2: These boards use BBCode as I added to your signature.

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Boinc V 7.4.36
Win7 i5 3.33G 4GB NVidia 470

Done it and corrupted jobs.... even when telling the defragger to completely leave anything in the ...BOINC... structure alone.

Its a fable with respect to NTFS not fragmenting.... it will eventually as bad as FAT32 particular if lost of installs/uninstalls and userfiles are on disk i.e. defrag once in a blue moon.

I agree NTFS drives will fragment but file access is not as badly impacted as with FAT32. My old systems needed defraging every couple of weeks or the file access would start getting sluggish. This new system despite the many thousands of files added, modified and deleted in the last five months as yet to indicate any problems even with the drive nearly 90% full. I have defraged it once, but that was more on a whim then a real need.

I shut down boinc and defrag around once per fortnight (and take a backup at the same time). Defragging makes around a 1-5% performance difference on CPDN (the files get heavily fragmented after running for a few weeks).

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I've NEVER stopped BOINC, nor previously SETI@home, when doing defrag or virus scans. Virus Scans are done every night. Defrags are done irregularly, but on average once per week on each machine.

Defraging sortof helps to partially overwrite deleted files.
I like to run it mostly for nostalgic reasons rather than any significant performance reasons.

I've NEVER had an issue with BOINC and defrag or virus scan corrupting file.

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If Boinc is running, the files are in use and can't be defragged. Hence no performance improvement. If you're running short-term projects (i.e., ones that only take a few hours or days to run per WU) then the tasks will not have been run long enough to require defragging.

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I guess, defragmentation is no issue on Linux systems, right?

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BOINC 7.2.42 (x86_64) on Linux Ubuntu 16.04 (64 Bit), AMD APU 7850K 3.7 GHz, 32 GB RAM.

I recall the Windows 98 defragger having to stop and restart from the beginning if some other app writes to the disk while defragging is going on. Maybe Norton and more recent Microsoft defraggers don't need to restart but I shut everything else down while defragging. Regardless of the restarting thing it just seems like asking for trouble if apps are accessing the disk while defragging. Better safe than sorry.

XP and later no longer have to restart from the begining. It can still slow things down or cause other problems though. So it is a good idea to stop as much as possible before defragging.

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BOINC WIKI

BOINCing since 2002/12/8

i rarely shut anything down when defragging as i've got it running as scheduled tasks that run at night and never have any problems with BOINC. Defrag skips locked files anyway... of course that means that locked files aren't defragged though ;)

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i rarely shut anything down when defragging as i've got it running as scheduled tasks that run at night and never have any problems with BOINC. Defrag skips locked files anyway... of course that means that locked files aren't defragged though ;)

What you write is just fine.

What is your experience with the following scenario: an application produces a large file in several steps (or, alternatively, has a large file which gets appended and changed from time to time). When that file is not being updated, it is not locked. When a defragging programme comes to such a file when not locked, it starts to defragg it. If that's done properly, defragging programmes houd lock that file. If that file is a large one, then it gets locked for extended period of time. What happens when original application tries to update the file in question? It finds the file locked and may well just decide to crash.

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Metod ...

On cpdn we've had a number of workunit crashes caused by AV scanning with the WU running, but I don't recollect any reports of crashes due to defragging while running the WU. (Of course this doesn't mean it's impossible.)

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Sekerob said

It does but did not lead to full WU loss, rather upon booting, the last checkpoint save was being resumed from.... happened to me on CPDN and WCG and as mentioned regardless the BOINC dir exclusions

As far as I know, the option to 'keep in memory while suspended' only works when the WU is suspended. It prevents the WU from going back to the last savepoint. This option has never worked when boinc is exited. In this case a WU always goes back to its last savepoint.

So it would not be the defragging that caused the WU to go back to its last save/checkpoint. It would be the exiting from boinc.

That's what happens with cpdn WUs.

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