On 8/5/2013 11:27 AM, adfel70 wrote:
Thanks for your detailed answer.
Some followup questions:
1. Are there any tests I can make to determine 100% that this is a "not
enough RAM" scenario"?
For heap size problems, turn on GC logging. Look at the log or run it
through an analysis tool like GCLogViewer. If there are collections
that take a really long time, it could be that.
For OS disk cache problems, look at your iowait CPU percentage, which is
extremely easy on Linux/UNIX platforms because they almost always have
'top' installed. If you have good caching, this percentage should be at
or near zero most of the time. A sustained 10% or larger iowait is an
indication of a real problem, and even numbers smaller than 10% can
indicate there's an issue.
2. Sounds like I always need to have as much RAM as the size of the index
I this really a MUST for getting good search performance?
Typically you can run with less than the full index size, but when you
drop below 50%, the chances of having performance problems increase as
that decreases. An absolutely ideal size is 100% of the index, but
normally you don't really need quite that much.
Thanks,
Shawn
