Vista - Defragment versus moving files?

11-18-2008

I have tried to defragment a virtual disk file on a USB connected
drive (NTFS format) using both the built-in WindowsXP defragger and
the SysInternals Contig program. The VHD file is 25 Gb and there is 41
Gb free space on the drive. Not so many files either on the drive.

But it seems like the strategy these programs use is a bit flawed, it
seems like they try to keep the file placement on the disk basically
the same and just try to move certain parts of it together. The net
effect is that there are about 5-6 used areas on the disk with lots of
free space in between, and these sum up to the 41 Gb. But because of
the spread position of these chunks there is no unused space big
enough to house the complete VHD in one piece.

Why is there no switch for the defraggers to tell them to move all
files up front on the drive and leave the free space at the end? This
seems to be the best strategy to handle big files....
If I remember correctly this is exactly how the defraggers/compactors
used to work 10-15 years ago. But not anymore.

Maybe this function is available in some other compaction software?
If so, could someone please publish a link to such?

--

Bo Berglund (Sweden)

11-18-2008

PM wrote:

Quote:

>
> 1) Turn off undo disk
> 2) Run the defragger (look at the readme - you need to install it with
> the -i switch before use - it doesn't put anything in the registry
> and you need to copy one file to System32)
> 3) Run Precompact (this is included as a CD image with Virtual Server)
> 4) Turn off the virtual machine, Inspect the VHD file and Compact it.

Oops - step 5, re-enable Undo disk if required!

11-18-2008

A few fragments are not going to make any noticable difference to the VHD's
performance, especially if they're large fragments.
It takes such a long time to read through a 25GB file, especially on a USB
drive, that the extra ~8ms per fragment is not going to slow things down
much overall.

--
Dave Harry

"Bo Berglund" <boberglund@xxxxxx> wrote in message
news:lmn4i49jig8jbop82p53cffmte9mqkqjdj@xxxxxx

Quote:

>I have tried to defragment a virtual disk file on a USB connected
> drive (NTFS format) using both the built-in WindowsXP defragger and
> the SysInternals Contig program. The VHD file is 25 Gb and there is 41
> Gb free space on the drive. Not so many files either on the drive.
>
> But it seems like the strategy these programs use is a bit flawed, it
> seems like they try to keep the file placement on the disk basically
> the same and just try to move certain parts of it together. The net
> effect is that there are about 5-6 used areas on the disk with lots of
> free space in between, and these sum up to the 41 Gb. But because of
> the spread position of these chunks there is no unused space big
> enough to house the complete VHD in one piece.
>
> Why is there no switch for the defraggers to tell them to move all
> files up front on the drive and leave the free space at the end? This
> seems to be the best strategy to handle big files....
> If I remember correctly this is exactly how the defraggers/compactors
> used to work 10-15 years ago. But not anymore.
>
> Maybe this function is available in some other compaction software?
> If so, could someone please publish a link to such?
>
> --
>
> Bo Berglund (Sweden)

11-18-2008	#1 (permalink)
Bo Berglund n/a posts	Defragment versus moving files? I have tried to defragment a virtual disk file on a USB connected drive (NTFS format) using both the built-in WindowsXP defragger and the SysInternals Contig program. The VHD file is 25 Gb and there is 41 Gb free space on the drive. Not so many files either on the drive. But it seems like the strategy these programs use is a bit flawed, it seems like they try to keep the file placement on the disk basically the same and just try to move certain parts of it together. The net effect is that there are about 5-6 used areas on the disk with lots of free space in between, and these sum up to the 41 Gb. But because of the spread position of these chunks there is no unused space big enough to house the complete VHD in one piece. Why is there no switch for the defraggers to tell them to move all files up front on the drive and leave the free space at the end? This seems to be the best strategy to handle big files.... If I remember correctly this is exactly how the defraggers/compactors used to work 10-15 years ago. But not anymore. Maybe this function is available in some other compaction software? If so, could someone please publish a link to such? -- Bo Berglund (Sweden)
My System Specs

11-18-2008	#2 (permalink)
PM n/a posts	Re: Defragment versus moving files? PM wrote: Quote: > > 1) Turn off undo disk > 2) Run the defragger (look at the readme - you need to install it with > the -i switch before use - it doesn't put anything in the registry > and you need to copy one file to System32) > 3) Run Precompact (this is included as a CD image with Virtual Server) > 4) Turn off the virtual machine, Inspect the VHD file and Compact it. Oops - step 5, re-enable Undo disk if required!
My System Specs

11-18-2008	#3 (permalink)
Dave Harry n/a posts	Re: Defragment versus moving files? A few fragments are not going to make any noticable difference to the VHD's performance, especially if they're large fragments. It takes such a long time to read through a 25GB file, especially on a USB drive, that the extra ~8ms per fragment is not going to slow things down much overall. -- Dave Harry "Bo Berglund" <boberglund@xxxxxx> wrote in message news:lmn4i49jig8jbop82p53cffmte9mqkqjdj@xxxxxx Quote: >I have tried to defragment a virtual disk file on a USB connected > drive (NTFS format) using both the built-in WindowsXP defragger and > the SysInternals Contig program. The VHD file is 25 Gb and there is 41 > Gb free space on the drive. Not so many files either on the drive. > > But it seems like the strategy these programs use is a bit flawed, it > seems like they try to keep the file placement on the disk basically > the same and just try to move certain parts of it together. The net > effect is that there are about 5-6 used areas on the disk with lots of > free space in between, and these sum up to the 41 Gb. But because of > the spread position of these chunks there is no unused space big > enough to house the complete VHD in one piece. > > Why is there no switch for the defraggers to tell them to move all > files up front on the drive and leave the free space at the end? This > seems to be the best strategy to handle big files.... > If I remember correctly this is exactly how the defraggers/compactors > used to work 10-15 years ago. But not anymore. > > Maybe this function is available in some other compaction software? > If so, could someone please publish a link to such? > > -- > > Bo Berglund (Sweden)
My System Specs

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