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Disk overload when DL torrents at 17 MB/s


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I/(we) made some more testing.

My friend just build a new "server". With a gigabyte MB with the new ICH9 chipset.

He bought 7 new HD's from samsung with 100+MByte/s throughput each.

Two is used as Raid0 with the system and 5 in a Raid5 config for storage.

As the MB has two separate Raid chip's they are both used separate.

A C2D CPU is used with 2.4 GHz.

We tested this outside of my FW/Router and managed to DL 38 MByte/s to memory (as I have a very quick connection), but only about 22 MByte/s from memory to disk, so we quickly ran into overload..

We tried with more that 1 GB of allocated RAM..

The quickets are the Raid0 disks.

But how should we do to get the data down to disk quicker?

In theory we should 2*50-100+MByte/s thoughput down to the disks, but we only get 22??

Where is the bottleneck?

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Random-access speeds can be a fraction of sequential speeds.

But even that's not the only bottleneck.

There's some caching issues with µTorrent that seems to limit it to that 22 MegaBYTES/sec you're seeing or lower.

...Some people haven't been able to get faster than 3 MegaBYTES/sec even on very fast internet lines or LAN transfers.

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I am now running 1.8 alpha.

It is much better in terms of disk write..

Now the bottleneck in the CPU at about 20 MBytes/s.

The diskwrites up to that speed can follow the DL speed to cache...

I am using an old laptop, so this is ok.

What is the difference between 1.7.5 and 1.8 regarding this?

Anyone else with the same experience?

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Windows cache is broken / not friendly to these random/non-sequential read/write. Yes your hard drive may report 4billion bytes/sec throughput, but its not random. For example I run stripe raid0 sataII on GigE. I can set as large a cache as I want but for any torrent you won't really see anything > 1.5x piecesize under Speed -> Disk Stats . Perhaps your hard drives ... also

Azureus work fine... do something with utorrent

It's not really µTorrent's fault windows cacheing blows. Also if you haven't noticed the devs are nice people, don't anger them please. They are actively developing µTorrent. Have you even tried searching the forum / requesting in the 1.8ß thread for the cache-tweaked build?

In any case Tin Man is on so I have to stop now. Oi! You people and devoting over half a gig of RAM... does it really add that much improvement? Modern hard drives have multiple tens of thousands of hours of MTBF, why isn't that good enough?

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Thanks for replay.

Some time I using Halite x64 C++ BitTorrent client based on the excellent libtorrent library from Rasterbar Software and it work fine with cashing, but it ander development and many futuares not implemented yet.Today I try again new build uTorrent 1.8 (8680) and with cashe setting on default


and ALL work FINE...disk not overloaded!I downloaded 2 files 5GB and 2GB with speed 4Mb\s and 3Mb\s in same time and my HHD working in normal mode, crazy spining absent...Thanks.Development go in right direction.

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