Hello, [...] >> Sounds nice, but please treat this as experimental feature and therefore be >> careful if your systems are mission critical, >> and your production environment cannot run into an inconvenience at any >> time. I would want to avoid breaking your infrastructure if possible :-) > > I'll plan to install patched Kernel on backup LVS node and perform tests by > directing traffic thru the slave node during night hours. [...]
Again, thank you for helping :-) > Could you please explain how exactly slow start mechanism works? In principle, the idea behind a slow-start (which only really applies to least-connection shedulers family) is to make a real server appear as a little bit busier than it really is in terms of number of active connections it handles, either when it is initially added to the pool or when its weight has changed. This will in turn lower the number of new connections that a scheduler will be keen on allocating to it and should prevent a real server from being overwhelmed by a substantial number of connections appearing suddenly for it to handle. In order to make that happen, we introduce a concept of artrificial handicap factor (we are simply making a real server less attractive, so to speak), which will decay over time allowing for more connections to be gradually handed over to the real server by the scheduler. I hope it makes sense :-) > Is there any configuration for slow start period of time, limit for maximum > connections or/and connection rate? At present, there is no way to set and/or adjust handicap factor (which is calculated automatically) and any other thresholds like maximum connections and/or connection rate. > For example, by now we are using the following shell script to bring up > failed real servers: > i=1; while [ $i -le 100 ]; do ipvsadm -e -t <VIP>:http -r <RS>:http -i -w $i; > echo "$(date +"%F %T") Weight set to $i"; sleep 10; ((i++)); done Are you starting with weight set to 0? > It is not the best solution because depending of servers load sleep interval > must be changed. Which is quite a manual procedure :-( > So limiting maximum connections or/and connection rate sounds more convenient. Perhaps a completely new scheduler should be introduced to address some of these problems, or perhaps we should expose some values from existing schedulers for users to tweak as needed. No idea at this point in time :-) KW _______________________________________________ Please read the documentation before posting - it's available at: http://www.linuxvirtualserver.org/ LinuxVirtualServer.org mailing list - [email protected] Send requests to [email protected] or go to http://lists.graemef.net/mailman/listinfo/lvs-users
