**  EXECUTIVE SOFTWARE PRODUCT NEWS  **

Diskeeper and Master File Table (MFT) Fragmentation

It's been said a number of times that MFT fragmentation can considerably
slow performance.  Let's take a closer look at why this is so, and how
Diskeeper restores performance lost to MFT fragmentation.

The Master File Table (MFT) is the heart of the NTFS file system.  It is
essentially an index to all of the files on an NFTS volume, containing the
file name, a list of file attributes, and a pointer to the file.  The data
for each file is contained in one record in the MFT, called the "file
record".  If a file is fragmented, then more than one pointer is required -
one for each fragment, in fact.  When the file system accesses a file, it
must first go through the MFT to obtain the location of that file, or the
location of that file's various fragments, as well as that file's various
attributes.

As one might surmise, an added MFT performance barrier occurs just due to
regular file fragmentation.  In that the file system must access the MFT and
obtain the location of every single file fragment AND THEN locate the file
fragments themselves, there is a lot of "double work" involved.  

But how does the MFT itself get fragmented, and what can be done about it?

First, it should be said that NTFS has a built-in feature which, under some
conditions, prevents MFT fragmentation from occurring.  The MFT is created
with a pre-allocated expansion space into which it can expand without
fragmenting.  There are a couple of conditions, however, under which MFT
fragmentation does occur, one of them being very common.  

Converting FAT to NTFS

The most common way the MFT gets fragmented is when a FAT partition is
converted to NTFS.  A FAT partition is converted to NTFS when such a
conversion is needed or desired, but it also occurs automatically during
Windows NT installation, if the NTFS format is chosen.  The partition
created during installation is a FAT partition, and even if the NTFS format
is chosen during installation, the partition is still created as FAT, and
only converted to NTFS after the first boot.  

When a FAT partition is converted to NTFS, an MFT is created.  If there is a
large enough contiguous free space, the MFT is made contiguous, with
contiguous pre-allocated expansion space.  However, since the MFT itself
plus the pre-allocated expansion space comprises about 12% of the partition,
there is usually not enough contiguous free space and the MFT is created
fragmented.  

Full or Heavily Fragmented Disks or Partitions

We covered the subject of the MFT's pre-allocated space above.  There is a
caveat to the MFT pre-allocated space, however.  NTFS, having been developed
to efficiently use every bit of space on a disk or partition, will utilize
the pre-allocated MFT space for normal files if the disk or partition
becomes full or heavily fragmented.  Simply said, if the disk runs out of
regular space for files or file fragments, NTFS will turn to the MFT's
pre-allocated space and begin writing files and file fragments to this
space.

When this occurs, the MFT can only expand by continuing its growth in
another space on the disk, a space not adjacent to the MFT.  Thus MFT
fragmentation begins, as when that space runs out, another space will have
to be found, and so on.  

Effect of MFT Fragmentation on Performance

When the MFT is fragmented, access to directories and files slows down
tremendously as the file system works its way through the fragmented MFT to
access the pointers and file attributes necessary to access every file.
Combined with regular file fragmentation, this is a performance nightmare -
the file system has to make multiple I/Os to access the MFT, AND THEN
multiple I/Os to access the file itself.

Before Diskeeper 5.0, there was no way to safely defragment the MFT, as it
is not safe to move online, while the disk or partition is live and in use.
Hence, one could defragment a disk or partition and clean up regular
fragmentation, but MFT fragmentation would remain.  (The author has personal
experience with a medium-used disk which was regularly defragmented, yet
ended up with an MFT in over 9,000 fragments.  Before Diskeeper 5.0, nothing
could be done about it, and simply opening Windows Explorer would take two
to three minutes.)

Frag Guard(r) to the Rescue

With Diskeeper 5.0, MFT fragmentation is no longer a problem.  With
Diskeeper's  Frag Guard feature, the MFT will be PREVENTED from fragmenting.
For the first time, a defragmenter has taken a proactive approach to
eliminating fragmentation.

Put Diskeeper, with its new performance-boosting Frag-Guard feature, to work
on ALL your Windows NT systems!  Contact your reseller for best pricing.