We do this at Flickr. tmpfs for rrds, and 10 minute rsync to persistant disk, and building the whole thing into the /etc/init.d/gmetad script.
No problems, really. We've tuned the 10 minute period a bit (used to do it more often) but other than that, no worries: ramdisk storage for rrds is good! -john ----- Original Message ---- From: Ofer Inbar <[EMAIL PROTECTED]> To: [email protected] Sent: Wednesday, July 11, 2007 1:09:23 PM Subject: Re: [Ganglia-general] RRDs in memory Matthias Blankenhaus <[EMAIL PROTECTED]> wrote: > First of, you need to reroute your data, e.g. to /dev/shm. So in > gmetad.conf I have the following: [...] > Secondly, in /etc/init.d/gmetad you need to create /dev/shm/rrds before > using it. So I have this: [...] > Thirdly, you need some logic to archive the rrds from /dev/shm/ to a > disk. Bernard Li <[EMAIL PROTECTED]> wrote: > You can also just mount /var/lib/ganglia/rrds as tmpfs: > > none /var/lib/ganglia/rrds tmpfs size=1024M,mode=755,uid=nobody,gid=root 0 > 0 It sounds like you've both done this. However, both of you leave out something I think would be important: after a reboot, how do you get the existing RRDs into place before gmetad begins, so that you maintain historical data rather than starting a brand new set of RRDs at each boot? Do you do this? With Matthias' method, you could add some more lines to the portion of /etc/init.d/gmetad that creates /dev/shm/rrds, to then rsync your RRDs from disk. That shouldn't interface with later restarts because if the directory already exists, it won't rsync. If you've done this, have you run into any problems? With Bernard's method, it is either mounted at boot time, or /etc/init.d/gmetad needs to check for it and mount it. If it mounts at boot, how do you handle copying the existing RRD files into place before starting gmetad? -- Cos ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Ganglia-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ganglia-general ____________________________________________________________________________________ Need a vacation? Get great deals to amazing places on Yahoo! Travel. http://travel.yahoo.com/ ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Ganglia-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ganglia-general
