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SHOW INNODB STATUS - FILE I/O - OS reads/writes/syncs?

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I've searched but with no luck... what do exactly these variables mean:

1343928 OS file reads, ********** OS file writes, 19976022 OS fsyncs

I am wondering if my innodb_buffer_pool setting is not to low. Does 'file reads' show number of times innodb files have been read into memory from server's start? What about file writes/fsyncs?

posted Jun 21, 2013 by anonymous

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1 Answer

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Best answer

these are the total number of reads/writes/fsyncs (number of system calls actually?) since the server started (or maybe last FLUSH call?) and not very meaningful by themselves without knowing the time span it took to come up to those counter values.

The per second values on the following line are much more interesting.

http://www.mysqlperformanceblog.com/2006/07/17/show-innodb-status-walk-through/

has a pretty good description of the SHOW ENGINE INNODB STATUS output, even though it is not too detailed in this specific section.

answer Jun 21, 2013 by anonymous
As I can see the changes in these values are use by percona cacti monitoring templates to graph "InnoDB I/O".
Can anyone answer the question finally? ;)
commented Jun 24, 2013 by anonymous
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