# "Disk Read/Write Time per IO Request (ms)" - problem **URL:** \ **Category:** Percona Monitoring Plugins\ **Created:** [August 13, 2015, 6:46am UTC](https://forums.percona.com/t/disk-read-write-time-per-io-request-ms-problem/4347 "2015-08-13T06:46:45Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Aoelo](https://avatars.discourse-cdn.com/v4/letter/a/dc4da7/32.png) [@Aoelo](https://forums.percona.com/u/Aoelo)\ **Post date:** [August 13, 2015, 6:46am UTC](https://forums.percona.com/t/disk-read-write-time-per-io-request-ms-problem/4347/1 "2015-08-13T06:46:45Z")
Fresh Cacti 0.8.8f. Fresh percona-monitoring-plugins-1.1.5 > > > > > > > > > > > > > > > > RRDTool Command: /usr/bin/rrdtool graph - –imgformat=PNG –start=‘-86400’ –end=‘-300’ –title=‘aten.test.rmv - Disk Read/Write Time per IO Request (ms)’ –base=‘1024’ –height=‘120’ –width=‘500’ –alt-autoscale-max –lower-limit=‘0’ –vertical-label=‘’ –slope-mode –font TITLE:10: –font AXIS:7: –font LEGEND:8: –font UNIT:7: DEF:a=‘/srv/www/cacti.test.rmv/htdocs/cacti-0.8.8f/rra/aten\_test\_rmv\_disk\_reads\_122.rrd’:‘DISK\_reads’:AVERAGE DEF:b=‘/srv/www/cacti.test.rmv/htdocs/cacti-0.8.8f/rra/aten\_test\_rmv\_disk\_reads\_122.rrd’:‘DISK\_writes’:AVERAGE CDEF:cdefa=‘c,a,/’ CDEF:cdefe=‘d,b,/,-1,\*’ CDEF:cdeff=‘d,b,/’ AREA:cdefa#75637EFF:‘Read Time per IO’ GPRINT:cdefa:LAST:’ Cur:%6.1lf%s’ GPRINT:cdefa:AVERAGE:‘Avg:%6.1lf%s’ GPRINT:cdefa:MAX:‘Max:%6.1lf%s\n’ AREA:cdefe#81BFE0FF:‘Write Time per IO’ GPRINT:cdeff:LAST:‘Cur:%6.1lf%s’ GPRINT:cdeff:AVERAGE:‘Avg:%6.1lf%s’ GPRINT:cdeff:MAX:‘Max:%6.1lf%s\n’ RRDTool Says: ERROR: invalid rpn expression in: c,a,/ > > > > > > > > > > > > > > > > > > > > > Data Source [DISK\_time\_spnt\_rdng] The data source to use for this graph item. and Data Source [DISK\_tme\_spnt\_wrtng] The data source to use for this graph item. is “none” Other graphs are okay. ---
**Author:** ![weber](https://avatars.discourse-cdn.com/v4/letter/w/da6949/32.png) [@weber](https://forums.percona.com/u/weber)\ **Post date:** [August 20, 2015, 1:56am UTC](https://forums.percona.com/t/disk-read-write-time-per-io-request-ms-problem/4347/2 "2015-08-20T01:56:45Z")
May be something changed with the new Cacti version. Giving percona-cacti-templates 1.1.5, cacti 0.8.8b I have got: /usr/bin/rrdtool graph - –imgformat=PNG –start=‘-86400’ –end=‘-300’ –title=‘cdba - Linux - Disk Read/Write Time per IO Request (ms)’ –base=‘1024’ –height=‘120’ –width=‘500’ –alt-autoscale-max –lower-limit=‘0’ –vertical-label=‘’ –slope-mode –font TITLE:10: –font AXIS:7: –font LEGEND:8: –font UNIT:7: DEF:a=‘/usr/share/cacti/rra/db1\_-_linux\_disk\_reads\_118.rrd’:‘DISK\_reads’:AVERAGE DEF:b='/usr/share/cacti/rra/db1_-_linux\_disk\_reads\_118.rrd’:‘DISK\_writes’:AVERAGE DEF:c='/usr/share/cacti/rra/db1_-_linux\_disk\_reads\_118.rrd’:‘DISK\_time\_spnt\_rdng’:A VERAGE DEF:d='/usr/share/cacti/rra/db1_-\_linux\_disk\_reads\_118.rrd’:‘DISK\_tme\_spnt\_wrtng’:A VERAGE CDEF:cdefa=‘c,a,/’ CDEF:cdefe=‘d,b,/,-1,\*’ CDEF:cdeff=‘d,b,/’ AREA:cdefa#75637EFF:‘Read Time per IO’ GPRINT:cdefa:LAST:’ Cur:%6.1lf%s’ GPRINT:cdefa:AVERAGE:‘Avg:%6.1lf%s’ GPRINT:cdefa:MAX:‘Max:%6.1lf%s\n’ AREA:cdefe#81BFE0FF:‘Write Time per IO’ GPRINT:cdeff:LAST:‘Cur:%6.1lf%s’ GPRINT:cdeff:AVERAGE:‘Avg:%6.1lf%s’ GPRINT:cdeff:MAX:‘Max:%6.1lf%s\n’ COMMENT:’ ’ COMMENT:’ ’ ---
**Author:** ![Aoelo](https://avatars.discourse-cdn.com/v4/letter/a/dc4da7/32.png) [@Aoelo](https://forums.percona.com/u/Aoelo)\ **Post date:** [August 21, 2015, 5:15am UTC](https://forums.percona.com/t/disk-read-write-time-per-io-request-ms-problem/4347/3 "2015-08-21T05:15:42Z")
Fresh Cacti 0.8.8b Only installed cacti\_host\_template\_percona\_gnu\_linux\_server\_ht\_0.8.6i-sver1.1.5.xml Same result! Something is missing! ---
**Author:** ![Aoelo](https://avatars.discourse-cdn.com/v4/letter/a/dc4da7/32.png) [@Aoelo](https://forums.percona.com/u/Aoelo)\ **Post date:** [September 3, 2015, 1:34am UTC](https://forums.percona.com/t/disk-read-write-time-per-io-request-ms-problem/4347/4 "2015-09-03T01:34:51Z")
HI! I can not give more information. What should I see? As I wrote to install only the cacti and cacti\_host\_template\_percona\_gnu\_linux\_server\_ht\_0. 8.6i-sver1.1.5.xml. And the variables c and d can not be any values. Is there anything templite is still necessary? ---
**Author:** ![Peter\_Sun](https://avatars.discourse-cdn.com/v4/letter/p/a6a055/32.png) [@Peter\_Sun](https://forums.percona.com/u/Peter_Sun)\ **Post date:** [January 10, 2018, 2:18am UTC](https://forums.percona.com/t/disk-read-write-time-per-io-request-ms-problem/4347/5 "2018-01-10T02:18:33Z")
> [@Ülo;42814](#): > > HI! > > I can not give more information. What should I see? > As I wrote to install only the cacti and cacti\_host\_template\_percona\_gnu\_linux\_server\_ht\_0. 8.6i-sver1.1.5.xml. > And the variables c and d can not be any values. > Is there anything templite is still necessary? Hi, I had the same problem, and I solved it. Here is how to solve it: 1. Edit Graph Template, search “Percona Disk Read/Write Time per IO Request (ms) GT” 2. In “Graph Item Inputs” you will find 4 items, click each to find out which one is configured wrong. In my config is [Data Source [DISK\_time\_spnt\_rdng]](http://192.168.1.87/cacti/graph_templates_inputs.php?action=input_edit&id=104&graph_template_id=44) wrong, it should be Item #4: GPRINT (MAX), but configured Item #8: GPRINT (MAX) 3. save and go to graph, you should see the correct graph. BTW, I am using Cacti 1.1.28 + Percona 1.1.7 templates, and I am using 1 minute interval. Hope percona can check the compatibility with Cacti 1.1.x and add 1 minute settings.