Performance tuning
Contents |
Opcode cacher
An opcode cacher compiles PHP code to Opcode, which means it won't have to be interpreted every time you visit a page. It will automatically detect if the code has changed and re-compile.
aptitude install php5-xcache
Multiple poller instances
One poller instance can only poll so much devices in the 5 minutes it has before it has to start again. Running different ones in parallel will allow Observium do check more devices in the same amount of time.
Syntax:
*/5 * * * * root /opt/observium/poller.php -i <number of pollers> -n <poller id> >> /dev/null 2>&1
Example for 8 pollers:
*/5 * * * * root /opt/observium/poller.php -i 8 -n 0 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 1 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 2 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 3 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 4 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 5 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 6 >> /dev/null 2>&1 */5 * * * * root /opt/observium/poller.php -i 8 -n 7 >> /dev/null 2>&1
Do note that increasing pollers will only increase performance until your MySQL database becomes the bottleneck, or more likely, when all the RRD writes to disk start to slow down the disk I/O.
Putting the RRDs on a RAM disk
See the separate Persistent RAM disk RRD storage page to find out how to set up a RAM disk with sync to the disks so you don't lose your data when your machine crashes/reboots.
Separate disk for MySQL
When all the I/O for the RRDs is clobbering your disk, your MySQL database will likely become slow too, due to disk congestion. This slows down the web interface as well. It is advised to put the database on a separate disk (separate hardware, not another LV on the same disk/RAID) for this reason.
Note that running your MySQL server on another machine increases the latency per query. When a lot of queries are done this could somewhat influence Observium's performance (however, moving MySQL to another machine than the one with all the RRD I/O could still prove to be a valuable enhancement).
Upgrade your uplink
Observium fires off a lot of SNMP queries to your devices. It has to wait for each reply to come back (per poller), before the poller can continue. If your uplink is congested, or latency to your devices is high, less devices can be polled in the same time frame. You could up the number of parallel pollers (if congestion is not the issue) or upgrade your uplink so more can fit through the pipe to remedy this somewhat (until we run into "speed of light in a fiber" issues).
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