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I have an old PC and I decided to revive it. A LAMP (for my own use) and a P2P server (torrent and e2dk).

My old PC is an AMD Athlon XP (1400 MHz) with 384 Mb of RAM

First of all I installed Ubuntu Server 11.10, SSH, FTP, SAMBA and LAMP. With this configuration my home server works well, with no problem.

Then I went to the P2P server and I tried rTorrent and then uTorrent Server Alpha. And here is my problem.

After a few hours (maybe 10 hours, or maybe 30 hours) with the torrent app running (rTorrent or uTorrent) I lose the connection to my home server. That is, I cannot access via ssh, I cannot access the apache server, etc. but I can ping the home server. It seems that the server freezes and all I can do is reboot the server physically.

So, I have two questions: What is the problem? and How can I solve it?

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1. Server Fault is for Professional IT only; home stuff is explicitly forbidden. 2. Sounds like you're running out of RAM. What does the console say when it freezes? –  Chris S Apr 9 '12 at 14:07
    
@ChrisS sorry and thank you for migrate my post. –  ilaz Apr 9 '12 at 21:58
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migrated from serverfault.com Apr 9 '12 at 14:07

This question came from our site for professional system and network administrators.

2 Answers

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RAM exhaustion is the usual cause for this, though relatedly you can also run into ulimit issues (with too many open files etc.) - every connection in Linux usually spawns a thread, and every thread is going to be an open file.

You have a torrent client running, so lots of open connections. With a default stack size that is going to eat up your RAM. If the client is smart and lowers the default (which is something like 8192 KB per thread, depending on your Linux version).

So, a couple of things to try:

  1. Raise your ulimit settings in terms of open files allowed (ulimit -n)
  2. Lower the default stack size (ulimit -s)
  3. Try running without the torrent client - does it still happen?
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Thank you for your answer and sorry for answer you too late :). Without torrent client running it's all ok. I think is more simple to add more RAM than set ulimit. So I'll try to upgrade my home server hardware with more RAM. It seems that the low RAM is the problem, right? –  ilaz May 9 '12 at 11:05
    
right - and if that is the case, then you should look into the ulimit -s options - if you lower the stack size per thread, then you may get more efficient operation of the torrent client. Alternatively try setting a connection limit per torrent - I generall see decent speeds with 40 per torrent and 200 max over all (so 5 fully active) –  Adam C May 10 '12 at 0:29
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I had a totally different setup but same sort of phenomenon. Computers couldn't talk to each other or outside world, or could sometimes in certain ways. I was sure it was on certain computer going nuts. Turned out to be the router needing a firmware upgrade. Apparently a bad router can make it look like one computer crashed. After that it was flawless ever since. Even though I suspect that's not your problem it may be worthwhile to check and be sure your router is okay.

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My router is up to date. I think is a ram issue. –  ilaz May 9 '12 at 11:04
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