prevent BitTorrent client from slowing down harddisk-access

[fuqnbastard]

Is there any way I can prevent harddisk intensive applications from slowing down all harddisk access (and thus my system) n-fold? This problem even affects the harddisks that aren't accessed by my bittorrent-client: I use a different disk for my shares and my programs. Yet when I run a simple python script to automate searching the web, it takes about 6 times as long with the client running.

Thanks!

[frostschutz]

You can try playing around with the 'elevator' kernel parameter in 2.6 - using another disk scheduler might help with your BT problem.

However, BT causes load for the disk by it's nature... files get up- and downloaded in random order, meaning random read/write access on the hard disk. The system's file cache is useless for BT; performance depends largely on the clients - some come with their own cache, and try to write bigger blocks in less random fashion. But either way you will have load on your disks, because files distributed by BT are usually CD or DVD images or the like, big files which can't be kept in RAM completely.

It should however not affect speed of your other drives, as long as they don't share an IDE cable and you have decent DMA support...

[fuqnbastard]

Those are both good ideas. I'm currently indeed running both harddisks on the same IDE cable, which is rather silly. And I'm gonna try with cfq as a disk scheduler and run my bittorrent client as a different user.
I just hope I won't run into too many problems readjusting my hardware/software configuration to the new device order...

[bexamous]

Azureus lets you choose a cache size, I don't know what other clients do. In the statistics tab it also reports how many read/writes the cache has saved.

I think 16MB is the default (at least what I'm using now) and writes it has saved 90.1%, reads has only saved 17.3%. If you have lots of ram you can make this cache any size you want... i think it gets useless to go over 64MB or so.