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Announcement regarding improvements to mackerel-agent’s Linux memory usage rate calculation method and specification adjustments

As stated in the title, with this week’s release of mackerel-agent v0.54.0, the calculation method for the memory usage rate in the new Linux has changed. With this new support, calculation of the memory usage rate is now more accurate than before. The following are supported.

  • Linux kernel 3.14 or later
  • Or environments where MemAvailable is backported to /proc/meminfo

Specifically, Ubuntu 16.04 or later, Debian 8 or later, CentOS 6.6 or later, Amazon Linux 2014.09 or later, etc.

Along with this, the display and items of stacked graphs for system metric memory regarding the target host have also changed. The specifics are as follows.

  • Existing environments: used + buffers + cached + free = total
  • Target environments: used + available = total

In contrast with existing environments, only “available” is stacked along with “used” and displayed in the target environments. This is due to the fact that the breakdown of Linux memory usage has become more complex in recent years, and “buffers” and “cached” are no longer necessarily freeable memory.

With this change, it is now possible to obtain a more accurate memory utilization rate. However, because there is a possibility that the value trend may change, please take the time to review your monitoring settings and such as necessary.

Thank you for choosing Mackerel.