Free Space

[John R]

At what point does the level (%) of free space on a disk become a concern
that needs to be addressed?

 

[Wesley Vogel]

15% if you want to defrag.

[[A volume must have at least 15% free space for defrag to completely and
adequately defragment it. Defrag uses this space as a sorting area for file
fragments. If a volume has less than 15% free space, defrag will only
partially defragment it. To increase the free space on a volume, delete
unneeded files or move them to another disk. ]]
Defrag
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/defrag.mspx

[[Although the defragmentation tools can partially defragment volumes that
have less than 15 percent free space, for best results delete unneeded files
or move them to another volume to increase the free space to at least 15
percent. You can also use the Disk Cleanup tool to delete unnecessary
files. For more information about Disk Cleanup, see Windows XP Professional
Help.]]
Before Using the Disk Defragmentation Tools
http://www.microsoft.com/technet/tr...prodtechnol/winxppro/reskit/prkd_tro_oegv.asp

--
Hope this helps. Let us know.

Wes
MS-MVP Windows Shell/User

In

 

[Ken Blake, MVP]

At what point does the level (%) of free space on a disk become a
concern that needs to be addressed?

Leaving aside the issue that Windows defragmenter needs 15% free space to
run, I would be much more concerned with the *amount* of free space than
with the percentage. You need enough space for you to add the files that you
want/need to add, and it's very difficult for anyone but you yourself to
address how much that is.

 

[R. McCarty]

In addition, when a drive ( with a single partition/volume ) reaches a high
% of use you'll start to notice performance degrading. This is due to the
fact that performance across the entire surface of a drive is not linear. As
you use more and more space the heads must travel further to reach the
data. You can see this graphically with any number of drive benchmarking
utilities available on the web. I use an external SATA drive and it's speed
varies from 67 Meg a second to as low as 37 Meg across the entire disk
surface.

 

[Ken Blake, MVP]

In addition, when a drive ( with a single partition/volume ) reaches
a high % of use you'll start to notice performance degrading. This is
due to the fact that performance across the entire surface of a drive
is not linear. As you use more and more space the heads must travel
further to reach the data. You can see this graphically with any
number of drive benchmarking utilities available on the web. I use an
external SATA drive and it's speed varies from 67 Meg a second to as
low as 37 Meg across the entire disk surface.

However note that the same degradation can occur with multiple partitions if
the last partition is fuller and more heavily used than the first ones (you
intimate much the same thing when you say "with a single partition/volume").
This is not simply an issue of percentage used.

 

[Paul Johnson]

Please don't quote in backwards order.
http://wiki.ursine.ca/Best_Online_Quoting_Practices

In addition, when a drive ( with a single partition/volume ) reaches a
high % of use you'll start to notice performance degrading. This is due to
the fact that performance across the entire surface of a drive is not
linear.

That's only part of the story: Fragmentation is only your enemy if the
filesystem has no internal method to deal with it efficiently. At this
point, the only filesystems that don't deal with fragmentation efficiently
still in circulation are ntfs, vfat and msdos. However, the root of the
problem has more to do with the fact that Windows only supports ntfs, vfat
and msdos filesystems. Pretty much every other filesystem has some sort of
understanding a block device's nonlinear nature and fragments files to
favor best disk performance; a 90% full filesystem performs generally as
well as a 90% empty filesystem. On such filesystems, defragmenting is not
necessary (even considered harmful).

The real shame in this is that there's no reason Windows can't or shouldn't
support other, better filesystems other than vendor lock-in.