Hello, Willy, thanks for you email. I will try to fight with the opts and memory? I hope it helps also for "low memory". We have 4GB on our 2 nodes servers.
On Tue, Nov 16, 2010 at 11:59 AM, Willy Tarreau <[email protected]> wrote: > Hello, > > On Wed, Nov 10, 2010 at 04:09:56PM +0100, Miko?aj Radzewicz wrote: >> Hello, >> I have a problem with haproxy and low memory usage. We have small 2 >> nodes GFS cluster. On both nodes we installed haproxy, apache, php, >> proftpd. The thing is when the number of request is higher, process >> are being killed. It seems that the server become run out of low >> memory and oom-killer starts to kill processes to free a bit of it. > > That can indeed happen on servers with too low memory. > >> The problem arise when we use haproxy.... When we do not use the proxy >> it is OK. Is it possible to do sth with it? Maybe we have to compile >> haproxy with non-defaults opts? The some things happen on the other >> server with only lighttpd installed... I would rather not to install >> 64bit OS. > > I tend to build it with -DBUFSIZE=8030 -DMAXREWRITE=1030. That divides > by almost two the memory usage. On average you should consider about > 17 kB per connection (2*8kB for buffers, 1kB for session). You must > also consider the kernel's socket buffers, which tend to be a lot higher > by default : > > $ cat /proc/sys/net/ipv4/tcp_rmem > 4096 87380 4194304 > $ cat /proc/sys/net/ipv4/tcp_wmem > 4096 16384 4194304 > > The middle number is the default buffer size for read and writes for each > socket. The leftmost is the minimum size (in case of memory shortage). > This means that by default, one connection will consume 2*(87380+16384)= > approx 200 kB of RAM in the system, but when memory starts to become scarce, > the system will still use 2*(4096+4096) = 16 kB. That's why I think that the > values above are reasonable : 17 kB for haproxy, 16 kB for the system. We're > at 33 kB total per connection. 1000 connections will require 33 MB of RAM. > > In my experience, with the OOM killer and server components which need > reliable operation, you should always set overcommit_memory to 2 and > overcommit_ratio to a value that suits your usage (40-70% depending on > the system and memory size). It will cause a malloc() to fail when there > is no RAM, instead of pretending the memory is allocated and crashing > the process when it tries to use it. > > Doing so, you'll notice that your system allocates more memory than it > really needs, but overall on servers the difference is low and it ensures > very reliable operations (you don't need to run firefox or any such thing > in such an environment). > > How much RAM do you have on your system ? > > Regards, > Willy > > -- Pozdrawiam, Mikołaj
