Fragmentation and Pre-Allocate

[dezzo]

Since upgrading to 1.8, all of my torrents are highly fragmented.

With 1.7, I used Sparse Files, and after turning on Pre-Allocate, the fragmentation dropped to almost nothing. I barely had to defrag my disk at all.

With 1.8, Sparse Files are on, and so is Pre-Allocate, yet I'm getting tens of thousands of fragments per torrent now.

The uTorrent FAQ says that Pre-Allocate has no effect on fragmentation, however in forum posts that I've seen, one of the administrators says that using Pre-Allocate DOES prevent fragmentation.

I've also read that Pre-Allocate overrides the Sparse Files option, but I've also read that Sparse Files overrides Pre-Allocate.

With all this conflicting information, it's hard to know what the hell to think.

Basically, I just want to download files with the least fragmentation possible. What settings do I actually need to use in uTorrent 1.8 to accomplish this???

And, are there any drawbacks to using those methods?

Thanks to anyone who can help clear this up.

[thelittlefire]

Sparse files on/off affects whether you actually use the space immediately. Fragmentation usually increases as your disk becomes full... i.e. the Windows allocation method doesn't have full range for full file allocation.

Either clear your disks more, or work with no incremental saving to disk (sparse_files OFF)... you could try increasing the disk cache or turning off write saved pieces immediately (changes to a 20 sec cycle) to make longer writes.

[Firon]

Pre-allocate was intended to override sparse files in 1.8. However, due to a bug, it did not. So sparse files are in effect here. 1.8.1 will fix this.

However, you should disable sparse files anyway.

[hermanm]

You can stage your downloads on a separate drive, then when the torrent completely, move it to a different hard drive.

[zeelurker]

fwiw - I don't think having a lot of free hard drive space helps with the fragmentation problem. I downloaded a 2.4 GB file with utorrent 1.8 build 11813 and it had 15,000+ fragments despite having 650 GB of freespace on a 750 GB drive. Even 30mb to 50mb files are turning up with 30 to 50 fragments. Hopefully, firon's suggesting turning off sparse files will improve this until 1.8.1 stable is released.

[Firon]

NTFS is really, really bad at allocating space...

[zeelurker]

fyi - Turning off sparse files worked fine.

[dezzo]

If you turn off sparse files and use pre-allocate, can you still use selective file downloading?

And if you can, if you disable certain files in the torrent from being downloaded, will the pre-allocate still allocate the entire torrent size on the disk, or will it only allocate the room for the files you have chosen to download?

[thelittlefire]

err, selective downloading is only disabled for those who use compact allocation. As far as pre-allocate with skipped files.. You only allocate the space for the files you download, but remember it may be up to 8 MiB per file (based upon piecesize) additional for the -partfile.dat for each file you skip.