I rolled out collectd 4.8, running in each of about 20 LXC jails. The I/O load was crippling the server, so I reduced polling with "Interval 60" in each jail.
However I would prefer to - poll every 10s (the default); - batch write RRDs, such that any given RRD is only written once every ten minutes; and - distribute these writes more-or-less evenly over time, i.e. avoid a huge I/O spike on the tenth minute. IIUC that means I should use this config: Interval 10 CacheTimeout 600 RandomTimeout 300 But this doesn't seem to be improving matters. Polling dm-25 (the filesystem mounted at /var/lib/collectd) every ten seconds, before the change: Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn dm-25 163.70 16.80 1292.80 168 12928 dm-25 88.90 4.00 707.20 40 7072 dm-25 279.20 8.80 2224.80 88 22248 dm-25 302.40 8.80 2410.40 88 24104 dm-25 122.40 7.20 972.00 72 9720 dm-25 386.90 7.20 3088.00 72 30880 After the change: Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn dm-25 33.20 11.20 254.40 112 2544 dm-25 292.10 12.00 2324.80 120 23248 dm-25 297.50 15.20 2364.80 152 23648 dm-25 41.90 8.80 326.40 88 3264 dm-25 428.30 4.00 3422.40 40 34224 dm-25 283.60 4.80 2264.00 48 22640 Is that wrong, or am I just expecting too much of buffered rrd writes? _______________________________________________ collectd mailing list collectd@verplant.org http://mailman.verplant.org/listinfo/collectd