Troy Nancarrow (MEL) schrieb: > Hi, > > Please forgive me if my searching-fu has failed me in this case, but > I've been unable to find any information on how people are going about > monitoring and alerting regarding memory usage on Solaris hosts using ZFS. > > The problem is not that the ZFS ARC is using up the memory, but that the > script Nagios is using to check memory usage simply sees, say 96% RAM > used, and alerts. > The options I can see, and the risks I see with them, are: > 1) Raise the alert thresholds so that they are both (warn and crit) > above the maximum that the ARC should let itself be. The problem is I > can see those being in the order of 98/99% which doesn't leave a lot of > room for response if memory usage is headed towards 100%. > 2) Alter the warning script to "ignore" the ARC cache and do alerting > based on what's left. Perhaps with a third threshold somewhere above > where the ARC should let things get, in case for some reason the ARC > isn't returning memory to apps. The risk I see here is that ignoring the > ARC may present other odd scenarios where I'm essentially ignoring > what's causing the memory problems. > > So how are others monitoring memory usage on ZFS servers? > > I've read (but can't find a written reference) that the ARC limits > itself such that 1GB of memory is always free. Is that a hard coded > number? Is there a bit of leeway around it or can I rely on that exact > number of bytes being free unless there is impending 100% memory > utilisation? > > Regards, > > > *TROY NANCARROW* >
the ZFS evil tuning guide contains a description how to limit the arc size. Look here: http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Solaris_10_8.2F07_and_Solaris_Nevada_.28snv_51.29_Releases Concerning monitoring of ARC size, I use (of course) my own tool called sysstat. It shows all key system metrics on one terminal page similar to top. You can get it there: http://www.maier-komor.de/sysstat.html HTH, Thomas _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
