Why does scheduled defrag ruin a disk with 0% fragmentation?

[guermantes]

Hi,

I was slightly annoyed that Defraggler (scheduled to defrag the drive in question twice a week) never managed to completely defrag one of my storage drives, 2Tb about 50% full. So I ran a manual defrag on the drive. It took about 16 hours to complete and afterwards there was 0% fragmentation and all file blocks were in perfect sequence - files at the beginning, free space at the end. I let the scheduled defrag setting remain active, though, for future purposes.

 

Today was a day for scheduled maintanance and I was wondering why my CPU fan kept revving all afternoon for no apparent purpose, until I checked Defraggler and discovered that the drive in question has been massacred fragmentation-wise. There was 0% fragmentation yesterday, and today 1 year-old large files have been torn apart into thousands of fragments. I had added some files to the drive - 20 or so RAW photographs - but in case they were fragmented, there was 40% free space to place them on the drive, without needing to rip apart non-fragmented 1Gb files.

 

1) I understand that when Defraggler sees fragmented files and is told to defragment according to schedule it performs some calculations of how to place the files on the drive. But with so much free space, why rip apart 1Tb of 0% fragmentation to defrag 160Mb of fragmented files?

 

This is extremely annoying since recently the scheduled defrag operations freeze my computer for a few seconds.

[mta]

OS version?

DF version?

 

have you set DF to turn off VSS, hibernation & paging file access?

[guermantes]

Win 7 x64

Defraggler 2.19.982 64-bit

VSS: No I have not ticked "Stop VSS during defrag on NTFS volumes"

Hibernation: is turned off at the system level, but DF was set to exclude.

Page file access: I cannot find that option in the settings. (Page file is on different drive, btw)

[mta]

forget pagefile (my mistake - I was having a brain-fart)

 

these are the ones to check;

http://forum.piriform.com/index.php?showtopic=35458&p=212223

[guermantes]

forget pagefile (my mistake - I was having a brain-fart)

 

these are the ones to check;

http://forum.piriform.com/index.php?showtopic=35458&p=212223

Those were already all checked.

And in any case, both hibernation and restore points are turned off at system level.

 

I don't understand why DF algorithm would see the need to start rearranging huge files when there is 50% disk free to place a few small ones that are new.

[mta]

in that case I sadly have no explanation.

 

you could try doing a manual defrag.

click on the File List tab, Analyse, sort by Size, select the worst offenders and Defrag Highlighted.

then sort by Fragments, selecting the worst and Defrag Highlighted.

also an opportune time to right click and Move Highlighted to End of Drive, if so desired.

[hazelnut]

Just in case, and for further info see here

 

http://www.piriform.com/docs/defraggler/defraggler-settings/defraggler-options-defrag-tab

 

 

Note: If you select Move large files to end of drive but do not specify file types, Defraggler will attempt to move all files equal to or larger than the size in the Minimum file size text box.

 

Default is 250MB

[guermantes]

Just in case, and for further info see here

 

http://www.piriform.com/docs/defraggler/defraggler-settings/defraggler-options-defrag-tab

 

 

Default is 250MB

Thanks, but I don't move large files to end of disk so that does not apply to this problem.