MFT reserved area

[Magilvia]

I used JKdefrag with much satisfaction on a number of different systems and I noticed that sometimes there's a huge pink area on some partitions and sometimes there isn't. Searching this forum and Internet I quickly found out this is the MFT reserved area and it's empty and unused unless the drive really fills up.
But I don't understand why it should occupy such a big chunk and nearly always at the beginning of the partition, in the fastest area of the disk. I would like to USE that fast area for something useful like my files and move this area at the end of the partition. How can I do this ? The forum showed nothing. Pheraps if I artificially fill my drive up to 100%, remove the added files and then defrag I could make it?
And Jeroen, thank you very much for this great program!

[JDPower]

Pheraps if I artificially fill my drive up to 100%, remove the added files and then defrag I could make it?

That does work but if you use JKDefrag with it's free space at the start it will only be a temporary solution as Windows will add the reserved space back into that gap at the start. Then you'll run JKD and it will have to re-add the free space and then Windows will expand the reserved space to fill the gapetc etc. So eventually you will end up back at square one.

My solution to reduce the impact is to keep my OS partition small (with about 30% free space) as the reserved space is calculated as 12% of the drive/partition size so reducing the partition size will reduce the reserved space size, resulting in your file data being a bit nearer the start of the disk

[jeroen]

The MFT reserved area is allocated by Windows when the disk is formatted. The size is a legacy from when harddisks were much smaller, but today is way to big for most computers.

I know that Vista (and maybe XP) will automatically shrink the reserved area, but I don't know why or when. Filling the disk is certainly a way to force the size down, I don't think it will (automatically) grow again once it is small.

[jarvis]

Certainly the MFT is positioned when the volume is formatted.

But since Windows 2000, isn't the MFT reserved space determined by the NTFS disk driver (ntfs.sys) when the volume is mounted?  Hence you have that registry key that can tell it to use up to 50% of the drive for the MFT reserved space (but unfortunately, no less than 12%).

Normally with volumes formatted as NTFS, the reserved space doesn't move much.  But if you have a FAT32 drive, and convert it to NTFS, the reserved space can jump around from occasionally.  Invariably it is not immediately adjacent to the MFT because other files are in the way, so expansion of the MFT causes fragmentation as the new extents are in the MFT reserved zone.  Then, if you defrag the MFT (e.g. Diskeeper, Perfectdisk) the MFT reserved space goes somewhere else again. 

At least, in my experience!

[Lundholm]

I know that Vista (and maybe XP) will automatically shrink the reserved area, but I don't know why or when. Filling the disk is certainly a way to force the size down, I don't think it will (automatically) grow again once it is small.

Oh yes, it will. Today my MFT zone completely disappeared but was recreated after boot. NTFS on XP pro SP2++.

Yesterday, it was the normal 12,5 % at about 1/3 up. Now it is sitting between zone 2 and 3, next to the MFT. That is 1% only! 

Cool! Absolutely perfect! But how can I keep it there in the future? Good ideas are welcome. 

[Lundholm]

But how can I keep it there in the future?

Well, this pleasant situation only lasted one night. This morning, the MFT zone was reallocated as 12,5% after zone 3. If anybody finds out what's going on, I'd like to know.

[jeroen]

If anybody finds out what's going on, I'd like to know.

So would I. All I can tell you is that the reserved space on my disks is much less than 12.5%. For example 50512 clusters out of a total of 12799999 clusters on my C: disk, which is 0.39%. It was 12.5% when I first formatted the disks, was shrunk by Vista in the course of some months, and is now stable (or at least I haven't noticed any change).

[Lundholm]

It was 12.5% when I first formatted the disks, was shrunk by Vista in the course of some months, and is now stable (or at least I haven't noticed any change).

Maybe Vista's handling of the MFT has been optimized, compared to XP?

Maybe your disks are more full than mine? My C partition is fairly large, so it is only 10% full. Maybe XP is still in the process of deciding how big/small the MFT should be?

[Eric2]

I don't know more unfortunately than what was already said.
I 'd like already to reduce the size of MFT reserved zone but dont know whether it is possible under XP Sp2.
I only know it should be possible when mounting a partition and installing XP pro Sp2 to have a very small MFT Zone (much less than 12% of total size) because it is the case on all my offices PCs and laptops.

[Lundholm]

I only know it should be possible when mounting a partition and installing XP pro Sp2 to have a very small MFT Zone (much less than 12% of total size) because it is the case on all my offices PCs and laptops.

It could be explained by these PCs having more data.  I think that the MFT zone allocation algorithm could be something like this:

Windows continuously recalculates the size of the MFT zone as the disk fills up, probably when predefined thresholds are reached. If you have a lot of small files, the required MFT will be large, and if you have a few large files, the required MFT will be small. If you move up and down around a threshold, the MFT zone allocation will move up and down. Not a perfect design, but it is a possible explanation.

Most people just slowly fill up their disk (they never uninstall anything, or delete any data), so they won't  see any strange behavior. Personally, I have the habit of making a general cleanup - like deleting old restore points - before running a sorted defrag. This of course affects the disk usage, and could explain why the MFT reallocation seems to occur in connection with a defrag - JKD's only fault being that it makes everything so visible. 

[Eric2]

It could be explained by these PCs having more data.

No they've got a small MFT reserved zone (pink area) from begining. For instance on one PC  Used space=14.4GB  and Free space=60GB   and I hardly see a pink area line after running Jkdefrag 3.33.

[Lundholm]

The mysterious behavior on my system seems to be reproducible at this stage. When I clean out restore points and do a sorted defrag, the MFT zone is recalculated as almost nothing after the next boot.

The second boot recalculates the zone again as 12.5% placed somewhere convenient.

Hmmmm?

[Myriades]

hi LundHolm
Does your mft has grown of 1 fragment? (I think yes)

I've already observe this on some computer.

Regards, Laurent

[Lundholm]

Does your mft has grown of 1 fragment? (I think yes)

Hi Laurent,

Yes the MFT is 2 fragments, which is quite normal, and it's been like that for a long time. Do you think that this causes the MFT zone to move around?

Cheers

[Myriades]

Do you think that this causes the MFT zone to move around?

I don't know, but it's an idea.

Does your "mft reserved zone" is just after the mft itself?
If no, I think that the next file creation will add a new fragment to your mft.

Regards, Laurent