[regression?] copying makes fragmented files

[wOxxOm]

I have a 1000GB new hard drive, no fragmentation (10% occupied), yet TC7.5 betas copy everything fragmented, however killcopy utility does not fragment (prealloc option enabled).
Options: Image: http://img233.imageshack.us/img233/7061/tc75copyoptions.png

btw, does TC use uTorrent's ultrafast method of preallocation? the one that claims new disk space without filling it with zeroes...

[Balderstrom]

Sparse Files

A file in which much of the data is zeros is said to contain a sparse data set.

The file compression in the NTFS file system is a partial solution to the problem. All data in the file that is not explicitly written is explicitly set to zero. File compression compacts these ranges of zeros. However, a drawback of file compression is that access time may increase due to data compression and decompression.

Utorrent: Speed up file allocation

When allocating large files uTorrent has to fill them with zeroes. That creates significant disk load and affects overall system performance. Windows XP provides a way to allocate files of any size almost instantly: SetFileValidData() function. It won't work without SE_MANAGE_VOLUME_NAME privilege (admin rights I guess) and with compressed files but I think it won't hurt anything in case of failure. Here is a link to small program that demonstrates this concept: http://depositfiles.com/files/8072561

In the latest version of utorrent, they've enabled the feature:
"diskio.no_zero"

Which from what I gather, is a workaround to the NTFS' feature that compresses large 0000 datasets.

============
Fix: of the first link, that Clo inadvertently broke w/ %40 %41's
Aside: 3 email notifications for this thread, and they're all discussing my msdn link. *chuckle*

[Clo]

2Balderstrom

[mod]I fixed the link to “Sparse files” in order to make it clickable
Just needs to code the damned parenthesis beloved by M$…
Clo, moderator[/mod]

[HolgerK]

2Clo,

small correction of your fix:

http://msdn.microsoft.com/en-us/library/aa365564%28VS.85%29.aspx

BTW: simply omitting the (VS.85)

http://msdn.microsoft.com/en-us/library/aa365564.aspx

should work too.

Regards
Holger

[Clo]

2HolgerK

I know this, that occured already, but I kept the URL exactly like Balderstrom wrote it…

 VG
Claude
Clo

[ghisler(Author)]

TC 7.5 now uses CopyFileEx for copying by default. I have no influence on how much it fragments or not. If you turn off the new default copy method, TC will use ReadFile/WriteFile again (which has other disadvantages), but in this case TC does pre-allocate the file space before copying the actual data.

[wOxxOm]

the developers of uTorrent had also rejected the trick to preallocate files without zeroing it... however the thread on that forum shows they've changed their mind, thus speeding up preallocation and eventually eliminating fragmentation (in most cases without any performance penalty)

[ghisler(Author)]

Did you try to turn off the new default copy method (which uses CopyFileEx), as I suggested? The old method did preallocate the space, but CopyFileEx doesn't have such an option.

[wOxxOm]

ah, now I see