Reserved system space question.

[Jeff]

I've got this color on my Diskkeeper map, which is shaded green and white on diagonal lines. Now that's reserved system space. I'm wondering how I could unreserve it, so I could get the space back, or find out how much it takes up?

I had used Cacheman XP to leave more space for the master file table, but when I uninstalled Cacheman, it was still there. I've got 12 GB of space used, but honestly, I really am using about 6.66 GB according to Folder Space. According to Windows I'm using 11.8 GB. Must be the reserved MFT space.

[TerminX]

jeffbthomson said:
Must be the reserved MFT space.


Not likely. It's probably all of your old system restore points slowly amounting to the discrepancy you're seeing.

[Jeff]

Hmmm. Turned off system restore and got about 5 GB of space back, but the green thing is still there at the same size.

[Bludd]

The reserved space isn't really unusable space for you. It's just that diskeeper will try to move data out of the reserved space when it defrags.

From the Diskeeper helpfile:


Green-striped areas (on Windows NT, Windows 2000, Windows XP, and Windows Server 2003 systems only) show space on the volume reserved for expansion of the MFT. This space is reserved when a volume is formatted, and cannot be used by applications, including Diskeeper. However, the operating system will write files to this area when the volume becomes extremely full and no other free space is available. Windows provides the capability for Diskeeper to move files out of this reserved area, but does not allow Diskeeper to move files into it. These areas appear only on NTFS volumes.



I suggest you read the help in Diskeeper. There's some good stuff in there.

Anyway, I thought this thread would be about the 8 MB (or so) that the WinXP installer's partition manager leaves unpartitioned when you partition a drive (geez, what a sentence!).

I tried once to resize a partition so that it would use up all the availible space on the disk, including those 8 MBs and after that, Windows became unstable. Bluescreens galore!

[Jeff]

It seems like that is a natural occurance for all drives. I didn't know this. It says that when the volume is near capacity the MFT reservation (green/white line) will shrink. Now mine isn't going to be anywhere near capacity, because even if I load it up with all the games that I have, that will only use 32 GB of space, which would fill half of those 2 drives in RAID. Reserving space for the MFT also increases performance of the drive.

I was worried that since there is that MFT reservation there, that Windows would spend more time looking for the files on the drive. Still confused on how this works. Although I have 5.2 ms access times and read/writes at 108 MB/s (sequential), it might spend more time looking for files, because of that space. So since it is used by Windows, does that mean that it would spend more time looking for my files on the other side of that? You know how a hard drive works. Drive looks for a file, and brings it to the front of the drive so it can be accessed. After x number of files have been accessed, this creates fragments...

Basically, I thought that the files to the left of the reserved space would be accessed quicker, and the files to the right of it would not. Or would Windows skip the reserved area, and go right to the files/directories on the other side of it.

[Scotty]

Files don't get moved to the front of the disk when they're accessed. The OS uses the FAT, MFT, etc to find the file and read it.

Due to larger circumference and fixed rotational speed, data can be read faster from the outside of the platters than the inside. Some defraggers could move the pagefile and other critical files to the outside to take advantage of this.

Some CD/DVD drives use Constant Angular Velocity to overcome this problem.