Missing hard drive space

  • Thread starter Thread starter Mike D
  • Start date Start date
M

Mike D

Hello,
On one of my DC's when I check the properties of the
disk it reports 63 GB used. However when I do a control
A at the rootof the drive and select all files and
folders and check the properties it reports the size to
be 13 GB. I individually checked every folder, and files
at the root of C: and it again comes to 13 GB. The C: is
the only partition. The hardware is three 35GB disks in
a hardware raid 5. So where is the 40 GB of disk space
that I'm missing going to? Thanks any ideas are welcome
I've been all over the internet with no luck.

-Mike
 
Does seem a little excessive. You didn't mention if you included the
pagefile and or any hidden, system files in the search. Also consider that
every file and directory listing (no matter what size) takes up at least one
cluster. Slack space is the area between the end of the file and the end of
the cluster. It can be calculated roughly by taking 1/2 of the drive's
allocation unit (cluster size) times the number of files, this is the
average wasted space. If you have a lot of small files then the wasted space
figure could be larger.

From a command prompt at the root of the drive in question;
chkdsk
to find out your cluster size (allocation unit)
 
Does seem a little excessive. You didn't mention if you included the
pagefile and or any hidden, system files in the search. Also consider that
every file and directory listing (no matter what size) takes up at least one
cluster. Slack space is the area between the end of the file and the end of
the cluster. It can be calculated roughly by taking 1/2 of the drive's
allocation unit (cluster size) times the number of files, this is the
average wasted space. If you have a lot of small files then the wasted space
figure could be larger.

From a command prompt at the root of the drive in question;
chkdsk
to find out your cluster size (allocation unit)
Click to expand...

Note that in both FAT32 and NTFS, cluster size increase with disk size. The
max for FAT32 is 32KB, and for NTFS is 64KB. Experience shows that while the
theoretical slack space is 1/2 cluster size, as Dave indicates, the _actual_
slack space tends to be closer to one-third (1/3) of diskspace. I think this
has to do with the kinds of files we create - mostly small documents. For
example, most e-mails are just a few lines. Even when they're composed in
HTML that makes for a small file, but they still take up a full cluster each.

BTW, some other OSs use 512byte allocation units. This slows disk access, but
the more efficient use of disk space makes that a small price to pay.
 
You say 63 gb and 13 gb and 40 gb. Try Chkdsk and see what it reports.
Remember 1 disk in a Raid 5 array is reserved for Parity.
 
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