hello all,
I am using defraggler and I noticed, that defragmentation is very slow - there are big breaks between degragments of every file. I checked disk usage when defraggler is runing (disk D:) - see attached image (win 10 pro). You can clearly see when it is defragmenting file (first is bigger, then there is series of small files) and whet it is taking holliday. What shall I do to use full disk performance ? Stop VSS is checked. Defraggler is the only program running. Thank you.
That's normal.
A defragmenter has to read file fragments from the disc, process the information into unfragmented pieces, then write files back to the disc in one piece.
Then it will read some more file fragments, process them, write them back, and so on until it has finished defragmenting.
So the disc will not be actively being read from the whole time, a lot of the time will be CPU processing then writing back the files and checking they have written back OK.
You should see that when the disk is not being read from/written to the CPU usage increases as it processes what it has read and writes them back.
Looking at your screenshot you can see that when the disc is being read the CPU is low, then the disc read stops and the CPU usage goes up.
So the big spike of disc usage was a read of a number of file fragments, and the following smaller spikes were writing back/checking of the files each in a single piece.
If that drive uses SMR (Shingled Magnetic Recording) defragmenting an SMR drive can be exceptionally slow.