Disk defragmentation

  • Thread starter Thread starter Lorne
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Lorne

This may not be an XP question but I could find nowhere to ask it.

I just bought a new 200Gb disk to replace my old (too small) backup drive.
Installed it as drive D, formatted as NTFS, and then copied all my backup
files from the old disk. I then had a look at it using the defrag utility
and was surprised to see 2/3rds of the used space in red signifying
fragmented files.

How can files copied once and never opened or altered after copying to a new
empty disk be fragmented ? It seems a hopeless way for disk writing in XP
to operate if it fragments files when they are written to an empty disk for
the first time.
 
That has been an issue with all Windows versions since the earliest of
days. Microsoft said that the issue was repaired in Windows 2000 SP3
but it wasn't.

Data Fragmentation Occurs When You Use Ntbackup.exe to Restore Data to a
Clean Volume
http://support.microsoft.com/default.aspx?scid=kb;en-us;297268

Says:

SYMPTOMS
After you restore data from a tape to a clean NTFS file system volume,
many of the restored files may be fragmented on the disk.
CAUSE
This problem occurs because Ntbackup.exe does not give NTFS any
information about how big the file that is being restored is. Because of
this, NTFS must pre-allocate standard size runs of clusters to hold the
file. This means that it typically allocates too much space that is
later returned to the free cluster pool when the file is fully restored.
These small runs are then used again for restoring later files, and this
caused file fragmentation to occur.
STATUS
Microsoft does not plan to resolve this problem in Windows NT 4.0. This
problem was first corrected in Windows 2000 Service Pack 3.

Based on discussions that I have had with another poster the problem was
not fixed even on Windows 2000 SP4. I appears that XP may have
inherited the same problem.

John
 
Thanks for the info - looks like very poor methodology by Microsoft to me.

Can you believe one of my files was copied with 24,747 fragments !!!!! It
was admittedly a large media file (609Mb) but that is ridiculous. Even
after running defrag once I still have 13 files with between 20 & 82
fragments apart from the one above that appears not to be affected at all by
defrag despite 45% free disk space.

Lorne
 
Yes, I agree. I thought it was a bit strange that the problem even ever
existed. I first experienced it with Windows 95 on FAT and Seagate
backup software. I then observed it on NT4 and Windows 2000 with both
ntbackup and Veritas BackUp Exec on NTFS. I never bothered with it
after I studied the "phenomena" on the Windows 95 machine, I just
accepted it as a bug and defragmented after restorations.

I have to agree with you the fragmentation is absolutely excessive and
from one end of the disk to the other. I would have thought that the
problem would have been fixed on XP, maybe it is, there might be a
switch of some sort when you do backups or restores but I don't know of
it, maybe someone else has a suggestion. The problem is especially bad
with large files because you might not have sufficient space to
defragment them, you can try restoring the large file only then defrag
it, and restore the rest of the files, a PITA for sure...

I had a similar discussion with another guy who had a similar problem
not too long ago, you can read what the other person had to say about
the problem here: http://tinyurl.com/p7cec

John
 
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