[Linux-HA] WARN: Gmain_timeout_dispatch
eric.robinson at psmnv.com
Fri Oct 16 06:13:13 MDT 2009
> Load is a very... debatable... metric.
Great article, thanks! Unfortunately, it falls far short of addressing
the current question.
The article is all about what the words "load" and "average" mean in
unix tools that show a "load average" metric. It clarifies two key
points: 1. "load" refers to the CPU run queue length and is indirectly
related to CPU utilization but not the same thing. It is basically the
number of running processes over time.; 2. "average" means a damped,
time-dependent average, not a simple numeric average. The article shows
how often the kernel calculates the numbers and what calculation it
These facts are not so much debatable as just misunderstood.
Unfortunately, it does not even begin to explain how the kernel could
*incorrectly* report system load, causing sar and top to give grossly
misleading output, and it does not address the critical "iowait" metric,
which is what I mainly watch because it indicates situations when
performance is disk bound.
In my situation, heartbeat is having trouble sending local status
updates, and it happens when the system *appears* to show high idle and
low iowait metrics.
Off to the kernel list...
Disclaimer - October 16, 2009
This email and any files transmitted with it are confidential and intended solely for General Linux-HA mailing list. If you are not the named addressee you should not disseminate, distribute, copy or alter this email. Any views or opinions presented in this email are solely those of the author and might not represent those of Physician Select Management and Physician's Managed Care. Warning: Although Physician Select Management and Physician's Managed Care have taken reasonable precautions to ensure no viruses are present in this email, the companies cannot accept responsibility for any loss or damage arising from the use of this email or attachments.
This disclaimer was added by Policy Patrol: http://www.policypatrol.com/
More information about the Linux-HA