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Disk overloaded with 400MB Disk Cache


akaidiot

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uTorrent disk cache seams to need some improvement.

I've got 100mbit/s connection and when I download at high speeds(2MB/s+) the disk cache get's full no matter how big the cache is unless the actual torrent is smaller than the cache size.

I've troubleshooted this and the problem doesn't seam to be that the size of the cache is to small. It's that uTorrent has problem keeping up with the sudden speed increase. Because if I manually increment the DL speed limit from 500kb/s when the downloading begins and then adding by 500kb/s to the dl speed limit up to 7MB/s I can download with a 40-200MB cache size without disk overloading.

To further investigate I tried using ABC 3.1 torrent client to download the same torrent that filled the cache instantly in utorrent and caused a disk overload and ABC had no problem with downloading the torrent at 4-5MB/s without me setting any speed limit and a moderate ram usage of 60MB.

Porhaps there there should be a high-speed mode in utorrent where utorrent itself limits the speed if it can't keep up with writing to the disk and when the cache has stabalized it will increase the speed limit with an increment of say 500 kb/s until it will eventually download the torrent at full speed which it has no problem with once I've babysitted the download up to 7-9MB/S

I thought I'd ask for your help before I report this as a bug/feature request.

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And it works fine for me at 8MB/s too. But only if I sit and babysit the dl speed from 500kb/s to 8MB/s, 500kb/s at a time. If I don't, I get disk overloaded.

My suggestion is to have uTorrent detecting the uncontrollable cache size growth and then slowly increase the DL speed. If not by default, an option would be nice.

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Yeah I know what you said, but what I'm saying is that it works without issue for other people, no babysitting required... I have no solution for this, as my connection is nowhere near that fast, but I only bring this point up because the fact that it works fine for most users with fast connections, up to gigabit even, I can't imagine it being a µTorrent problem in itself. I could very well be wrong, but at this point, I doubt it =T

Who knows, let's see if someone else can confirm/explain this.

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I'm sure the fact that I'm usig a laptop harddrive affects this. But what if there was a "slow hardrive mode" for utorrent where it would cap the download speed when the load on the harddrive is to heavy and not just cram the downloaded bits that aren't written to the harddrive fast enough to the cache/memory which results in a full cache and disk overloaded errors.

If I just gradually advance myself up to say 8 MB/s it downloads several GB fine and the cache stays at a reasonable level without even close to overlaod the disk so the harddrive can infact manage to handle the load if utorrent is smart enough.

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  • 2 weeks later...

i have the same problem too!! i use a friend's server that's co-located at an ISP. the machine has 1 Gbps connection. the babysitting is required if the files being added are bigger (say 10 GB) than the cache size. this might be related to a bug that's noted in the faq.

also, after a few minites the download speed would reach 8-9 MB/s. this is no problem at this speed. however, if the speed is higher than about 10 MB/s, the disk overloaded problem would be back!! i am guessing that bittorrent nature of getting random pieces (i.e. not sequential) of a torrent makes disk writes random and greatly reduces disk write speed. and that's what caused the disk overload.

is there a way to fix this problem for really high speed users? for example, instead of getting individual random pieces, get 100 contiguous pieces at random if speed is more than 5 MB/s. high speed users are not as rare as you might think. in thailand, bittorrent hosting on co-location servers is quite popular. you can rent say 50 GB of disk space and get the files shipped to your home in dvd's. :)

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Try net.low_cpu = true, spread the torrents out between multiple hard drives if possible, run fewer torrents at once, and use fewer upload slots at once (and DON'T check use more upload slots if upload speed <90%).

Hard drives are faster grabbing BIG chunks at once, so with fewer upload slots going each upload slot will presumeably be running faster...letting the hard drive grab bigger chunks of the torrent at once.

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