[SimonJester]

Am running NT W/S 4.0 sp6 in an all NT network, and some of the workstations (maybe all) are mis-reporting the amount of free disk space. If I manually add up all of the files and folders on the partition, there should be about 400MB of free space, but it is showing only about 100. I just found out about this, because someone had a problem installing something (not enough disk space). When I checked two other machines, they were doing the same thing. This is a fairly new network (12 machines, 1 PDC, 1 BDC, all running NT 4.0 sp6).

Help!?

[craigal]

What file system are the clients using. If they using FAT then this would cause a difference due to the cluster size of the drive.

Because the drive space is allocated in units of a certain size ( Could be 4K or more depending on the size of the drive ), the space used by a file is more than the size of the file. If you have lots of small files then the difference could be large.

[SimonJester]

They are using FAT16, BUT...

I am getting properties on every folder and file, and totaling up the REPORTED disk useage (not actual).

[Reuel Miller]

Greetings

This is fairly typical of the FAT16 file system. This is basically what is happening:

Your HD is formatted with FAT16, and this is what that means: On your HD, during a low level format, the disk is assigned tracks, and each of these tracks are split up into sectors (typically 512 bytes long). Then the disk is formatted by the Operating Sytem with it's filing system. The sectors are then grouped into Clusters.

With FAT 16, the cluster sizes are as such (this may be a little wrong, I am doing this from a very shaky memory) :

<PRE CLASS="FIXEDTEXT">
Drive Size FAT Type Sectors Cluster
(logical volume) Per Cluster Size
----------------- -------- ----------- -------
0 MB - 15 MB 12-bit 8 4K
16 MB - 31 MB 16-bit 1 512 bytes
32 MB - 63 MB 16-bit 2 1K
64 MB - 127 MB 16-bit 4 2K
128 MB - 255 MB 16-bit 8 4K
256 MB - 511 MB 16-bit 16 8K
512 MB - 1023 MB 16-bit 32 16K
1024 MB - 2048 MB 16-bit 64 32K </PRE>
So, as you can see, the larger you partition is, the larger the sector size is. Now, WinOS Filing systems can only assign ONE file per Sector. So, if you had a 1K file on a 2 Gig partition, then it will take up 32K of HD space. Similiarly, if you had a 33K file, it will take up 1 whole cluster and 1K of the next cluster, so, in total, it will be using 64K of HD space.

The way to save space is to either have smaller partitions or smaller clusters. The only way to have smaller clusters is to use FAT32 (which is unreadable by NT4, well, without the FAT32 reader by www.sysinternals.com) or to use NTFS, where on multiple Gig drives you can have clusters as small as 512 bytes (using the compression).

So, that is why your files of 1K are taking up to 32K of space....

Hope this helps

------------------
Reuel Miller
Windows NT Moderator (yes, that does make me biased )

rmiller@xperts.co.za

Every morning is the dawn of a new error...



[This message has been edited by Reuel Miller (edited 11-20-1999).]

[SimonJester]

Hi Reuel,

I appreciate your help, but I must not be making myself clear.

First of all, I am a veteran tech (14+ years), and understand very well how FAT16 differs from FAT32 and how small files can take up much more space on a large partition on FAT16 partitions. This is definitely NOT my problem...

The problem is:

I total up the total amount of disk space being USED (get properties on a folder, and take the number of actual disk space being USED for the folder/files) by ALL files and folders individually, and it does not match what Windows shows as being available (free) space on the drivbe when you get properties on the entire drive. It is off by as much as 400MB on one computer. It is NOT happening on all computers, just 4 of them (out of 12 total). The others are fine, and they all have essentially the same software on them (we do have net access for all computers, so it is possible someone has downloaded something that is causing this). I have run NAV (with latest VDF), but don't have a copy of Norton Utils yet (that's next on my list on Monday).

Any other ideas?

[LarryCore]

How about doing a quick reality check? I always find them useful...

Grab yourself a copy of TreeSize and see if it pins down the mystery for you. Who knows, maybe there are some hidden files or folders in there somewhere.
http://www.jam-software.com/treesize.html

[Reuel Miller]

Greetings

My apolgies, Mr Jester. I did not realise that you were a veteran (and to think I spent 30 minutes getting that table to look decent... D'Oh! )

It is entirely possible that there are hidden files on the PC, that you can not see when you are doing your manual check.

This is especially true of Temporary Internet Files, and files that MS "hide" from us.

Larry's suggestion is a good one. You need to have a look "under the hood", so to speak. Also, what you could try, if you have some time, is to boot the computers off a DOS stiffie, and have a look at the directory structure from a command prompt. It is amazing what you can find when you utilise DOS. And since the drives are FAT16, then this should not be a problem.

If you had NTFS drives, then you could go to www.sysinternals.com and download their utility called NTFSdos, which mounts NTFS drives so that they can be read by OS's from DOS 5 to Win98. This tool is a life saver, as even if you had NTFS permissions, the files can still be read in DOS with NTFSdos.

It is for that reason (now, that I am WAY off the topic, I might as well end it soon), that you should keep your servers with sensitive information on it physically safe, as well as logically (and networkly... if that is a word) safe. That message is directed to some of the newer NT admins, not specifically you, Jester.

Anyway....

[Reuel Miller]

Greetings

I just had another thought....

If you have the time and the other suggestions do not turn up anything.... convert one of the PC's drives to NTFS, with 4K sectors and see if there is any difference.

Just a thought

[SimonJester]

Alright...

Thanks guys, now I have a few things to try on Monday.

Also, thanks for the tips on the utils...I'm still relatively new to NT, and can use all the tips I can get.

Any suggestions for sites that have lots of NT goodies?

By the way, I like this forum...kudos to the ones responsible...