SHOUTcast DNAS 2.2 (Build 107) 10/16/2013 *** Forum Exclusive ***

[Cande]

Milosz,
during the last weeks, I've been encountering a lot of stability problems with sc_serv.
The service, which streams 15..20 different external sources (not using sc_trans) kept on crashing (mainly due to segfaults) several times per day, until I discovered version 2.2 of DNAS.
After the update, everything started to be much more stable, so the improvements and fixes introduced with the new DNAS are indeed effective, although some halts were still happening.

By studying the DNAS' logfiles I discovered weird entries, that I suspect are kind of "attacks": some IPs kept on connecting and disconnecting hundreds of times in seconds and some others even tried to use the server to start their own stream (SRC bad password errors).
To test if this was the cause of the crashes I started to ban the attackers' IPs (and in some cases entire netmasks since they were changing IP) via linux firewall and… boom, stability improved noticeably!

My last change to the installation was to rise the max open files limit to 4096, but I can confirm that during a test with "nofile limit" set to 65536 sc_serv crashed, so the standard 1024 value may be enough for DNAS to operate correctly (real time monitoring during an average load of about 200 connected clients shows 800..900 open files).

I have set a global limit of 500 users, but never go over 300 in the last days, so I cannot confirm your problem.

Hope that helps…

Cheers!
Cande

[DrO]

Originally Posted by Cande

By studying the DNAS' logfiles I discovered weird entries, that I suspect are kind of "attacks": some IPs kept on connecting and disconnecting hundreds of times in seconds and some others even tried to use the server to start their own stream (SRC bad password errors).
To test if this was the cause of the crashes I started to ban the attackers' IPs (and in some cases entire netmasks since they were changing IP) via linux firewall and… boom, stability improved noticeably!

which is already noted in the known issues -> http://forums.winamp.com/showthread.php?t=373139#known

under high loads, i know what the solution is and have most of the code written to do what's needed, but under testing it was not 100% stable and so was not included as part of the 2.2 release (as a still running DNAS which just stops processing connection requests is not useful - at least that's what it was doing on some test setups we had). however, as the vast majority of stations barely go over a hundred concurrent listeners, having something which is stable for the majority was the primary aim for the 2.2 release (and to ensure we've got something that in terms of general functionality is able to replace the v1.x DNAS at last as supporting v1.x listings is becoming a pain in a number of areas).

[Cande]

Originally Posted by DrO

which is already noted in the known issues -> http://forums.winamp.com/showthread.php?t=373139#known

Thanks for pointing out.

Please note that, right before the crashes I could closely monitor, I did never notice a high number of concurrent connections (Max Listeners never exeeded 250).

On the contrary, there were multiple and continuous connection attempts which disconnected after 0..2 seconds.

As I repeat, stability greatly improved by updating to version 2.2, but also the way sc_serv crashes changed.
Version 2.0 usually exited after a segfault (as seen in server's syslog), while 2.2 hangs/freezes and gives no reasons for that.

Thanks a lot for your great support!
Cande