Kernel Bug Tracker – Bug 15487
System hangs during retransmit of TCP ACK or SACK
Last modified: 2010-03-09 23:40:22 UTC
Created attachment 25419 [details]
System (highly loaded web server) accidentially hangs after several days after outputting crash dump. No reaction to keyboard or records in system logs. By this reason only last part of crash dump is accessible, screen copy is in attachment.
Problem was noticed in kernel 126.96.36.199. Then upgrade was made to 188.8.131.52.
Problem seems to be connected with my tunings of system variables. Here they are
net.ipv4.tcp_mem=786432 1048576 1572864
net.ipv4.tcp_rmem=4096 87380 1048576
net.ipv4.tcp_wmem=4096 32768 1048576
Other changed values unrelated to TCP.
Problem noticed on different hardware (Multiple Xeons with Intel's chipset and network cards, Multiple Opterons with nvidia's netword cards) with 16-32GB of memory. Never noticed before providing specified sysctl values.
Created attachment 25420 [details]
custom kernel config
Checked something. It seems that
enables this problem.
(In reply to comment #2)
> Checked something. It seems that
> enables this problem.
I meant together with other my tuning. As I never noticed this problem on server with
net.ipv4.tcp_rmem=4096 87380 2097152
net.ipv4.tcp_wmem=4096 131072 2097152
Or may be these tunings are unrelated.
*** This bug has been marked as a duplicate of bug 14470 ***