Rob Mueller a écrit : >> On current production platform the frontends use swap massively but the >> impact is far less than on the new platform. >> > > It's not so much how much swap is actually used, but how much is being paged > in or paged out at any time. If there are memory pages not being used at > all, the OS will swap them out, but that's fine because they're not being > used. > > The problem is when more memory pages are being used than memory available. > In that case the OS starts continuously moving things back and forth between > RAM and swap, which causes performance to become horrible. > > Can you run "free" and "vmstat 10 10" (will take 100 seconds to run) on one > of your old frontends and one of your new frontends during peak times so we > can get an idea of what is going on with memory + swap. > > Also lets just confirm a process count on your system. Run these commands: > > ps ax | wc -l > ps ax | grep imapd | wc -l > > On both old and new. > > >> We are indeed using 64bits OS and 64bits software. This is the main >> difference between the old platform which runs a 32 bits software on a >> 32 bits OS. >> > > That will increase memory usage as well. Every pointer in the system (either > in the kernel or in an application) is now using twice as much space. Of > course not all data is pointers, but depending on the application it can > mean considerably more memory is used. > > Lets start with the free, vmstat and ps data, and we'll go from there. > > We are currently gathering those data. They will be posted when available. Setting the TLS cache db to skiplist remove the locking errors we had. -- Eric ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
