High disk fragment?

[demos]

I use utorrent since 1.8 beta. Using it download several file, speed is great. But I found it creates huge amount of disk fragment. I leave most setting on default.

The red part are pretty much generate by utorrent. I have try to search the help file about fragment and finding that "diskio.sparse_files" have enable on my utorrent by default. Should that would be the reason it generate so many fragment?

[hermanm]

Yes, assuming your file system is NTFS. Here is an explanation of how NTFS sparse file works. I haven't done any extensive testing, but I don't think fragmentation will cause any performance issues unless you're running very high speeds like 100 Mbit+. And any time a torrent has to Force Recheck you might notice delays due to fragmentation. For seeding on a home broadband, the upload speed is the bottleneck and fragmentation will not affect throughput.

[Firon]

Yeah, it's probably sparse files. It's usually okay if only downloading a single torrent at once, but it can fragment a lot with multiple torrents (or a lot of files). MS implemented it poorly, it's supposed to pick regions so every file has the least amount of fragmentation, but it doesn't...

[demos]

I'm actually have 6Mb connection. I usually download one torrent a time, two at most. The torrent size are usually 500M~1.5G single or with few files.

uTorrent's speed are amazing though, it's much faster than bitcomet I used to use.

Try to download some 100M file with sparse_files turn off, didn't got more fragment now, hope it solve the problem

[kandy4me]

I've actually found that pre-allocating files doesn't change fragmentation at all... for a 700MB file, it can have over 2000 fragments.

Since the file is pre-allocated, why doesn't uTorrent just write the data as an offset of the start-bit once that peice is done?

[jewelisheaven]

pre allocation DOES NOT EQUAL contiguous. For that you should pick up Contig from the sysinternals folks @ http://sysinternals.com

[Firon]

If sparse files are enabled, it overrides pre-allocate (in 1.7.7, 1.8 changes it around), which can increase fragmentation.

However, if your free space is fragmented, it'll probably fragment anyway because Windows is dumb when it allocates files.

[Consigliere]

jewelisheaven

Contig is fine for defragmenting already fragmented files, however if there is enough contiguous free space uTorrent should allocate the entire downloading file in that area. It drives me crasy: I have ~250Gb free on hard drive and still have thousand of fragments of each downloaded file!

[Harold]

That's rather low-level and messy don't you think..

[Firon]

µTorrent doesn't control allocation. The NTFS filesystem driver does.

But turn off sparse files, as NTFS allocates those even more poorly than normal files.

[Consigliere]

Hi

You mean there is no way to prevent the problem of fragmented files from the very beginning? And I have to torment the HDD regularly with defrag?

[Firon]

Nope. There really isn't. If you have sparse files disabled and your files still fragment to hell, you can't do a thing about it.