pre-allocate disk space & select some files to download

[Kronos]

If select pre-allocate disk space in utorrent.

When select some files to download by

select 'Don't Download' in file tab.

It still pre-allocate every files including files that

select to 'Don't Download'.

[SledgeDG]

mmm..if I think about that a program first pre-allocates the space

Then you exclude some files...and now you expect to have some blocks of the pre-allocation freed again?

Doesn't make any sense to me, sorry

In that case why do you even preallocate in the first place?

but...If you choose to pre-allocate, unused blocks are freed automatically after the download finishes

are you so tight on space that everty MB counts? (been there myself before :D)

That was always the time for an additional, or bigger HDD

-DG

[bvisser]

I don't want to pre-allocate but it is always done, even when unselected.

Is this a bug?

[Firon]

It's not actually pre-allocating, it just reserves the space in the file table, but no data is written. It also doesn't do it until data is written to the file.

Pre-allocate allocates all files and zeroes them.

[bvisser]

OK, but why is there a choice for selecting or deselecting pre-allocation. As far as i see it, selecting or deselecting makes no difference. Or am I wrong?

[Firon]

Pre-allocates allocates ALL the files the moment you load the torrent, and writes 0 to all the file data. Without it, it only reserve the space in the MFT; no data is written to disk. In fact, it doesn't even reserve the space or create the file until a piece is downloaded.

[bvisser]

you download not a file at a time, when even a small piece of a file is downloaded it allocates the complete file. That means that when downloaded a kb of a gb file it allocates that gb? I found at the forum that diskio.sparse_files can do something for me in this case?

[Firon]

Yeah, it allocates the entire GB (by reserving the space, not writing 1GB of data, the key difference between having pre-allocate off and on). Turning on sparse files will help that, but keep in mind that it increases fragmentation. It's also for NTFS partitions only.

[bvisser]

Ok, thank you Firon. It is all clear now!

[Goph42]

But it is still not how it should work. The reason one has preallocation is so that it doesn't stop in the middle, because the harddisk space has run out (which would happen if You used sparse files). And it isn't necessary to reserve space for files You are not going to download.

I had added the torrent without pre-allocation and set up which files I wanted to download and then turned on preallocation before starting the download, and still it allocated the files I had marked as skip.

Someway to handle this would be very useful.

[chaosblade]

I somewhat agree, now that we have the partfile feature - useless data having to be downloaded and matchs those skipped files should just go to the part file, and none of the skipped files allocated.

[linuxares]

If I active this I will stop getting "D:\$Mft" writing error? This have started happening lately. I used Bitcomet before and other clients always filled up everything before downloading. So I will use this now I think it will help me