I'm upgrading our main router to include automatic failover. Up until now, I'm switched manually if one failed and copied the rrd files over to maintain data continuity.
Now I want to have both online and ready, keepalived should take care of switching in the backup if the master fails. Managing two data sets should be too hard, I just need to modify my data sources so I can do : if A is unknown then if B is unknown then Unknown else B else if B is unknown then A else A+B Or in RPN (I think !): A,UN,B,UN,UN,B,IF,B,UN,A,A,B,+,IF,IF However, if I have a router failure, then A or B may not be accessible. At the moment I access the data files via NFS, so the graphing always uses the most current data. My current thinking is to use rsync to copy the data files every few minutes from both routers to the graphing machine. That way, both sets of data files will always be available for graphing, and if a router is down, then the rsync will simply fail and that set of files will simply stop updating - returning unknown to the graphing code. The downside is that it will introduce a small extra delay before updates become available in the graphs, and it will incur load on all three machines whether I am doing any graphs or not. Alternatively, I'd considered populating the mount point of the NFS share with dummy (empty) rrds. Then I could unmount the share and the graphing would just access the empty files. It won't give me historical data though. Could this unmount when the NFS share is unavailable be automated ? Any other ideas ? -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
