innodb parition iops increase as partition grows

[Len Rugen]

This was prompted by a discussion on the #zabbix IRC channel, some of have had mysql iops grow during the day to a level that we couldn't support. I found that it was related to some particular tables that are partitioned by the timestamp of an event into 24 hour blocks. When a new day started IOPS was trivial, by 18:00, it was unsustainable. I just changed to partition every 4 hours, resulting in about a 4G partition size for the largest partitions. The IOPS still grow over the 4 hour interval, but not to a level that causes problems.

Our question, why would IOPS grow as the partition grows when the data rows written should remain fairly constant?

Thanks