Jay,
What OS, release and Tomcat version are you running? I've seen a similar
issue on another piece of software (Ramadda). Since I've seen this behavior
with the standalone server and the tomcat-based server, I'm beginning to
suspect my Java installation, but have not had sufficient time to
investigate yet.
There may be an OS correlation here, so I'm interested. I'm running RHEL 6
and the various updated flavors of OpenJDK and Tomcat6.
gerry
On Wed, Dec 11, 2013 at 4:33 PM, Jay Alder <alderj@xxxxxxxxxxxxxxxxxxxx>wrote:
> Hi, we’ve recently released a web application that uses TDS for mapping,
> which is getting a lot of traffic. At one point the server stopped
> responding altogether, which is a major problem. A quick restart of tomcat
> got it going again, so I’m starting to dig into the logs. We normally get
> the GET / request complete behavior, but occasionally we’ll have:
>
> GET …url…
> GET …url…
> GET …url…
> GET …url…
> GET …url…
> GET …url…
> GET …url…
> GET …url…
>
> meanwhile having a 100% CPU spike (with 12 CPUs) for a minute or more
>
> request compete
> request compete
> request compete
> request cancelled by client
> request cancelled by client
> request compete
> request compete
>
> While watching the logs the few times I’ve seen this occur it seems to
> pull out of it ok. However the time the server failed, requests were never
> returned. From the logs, requests came in for roughly 40 minutes without
> being completed. Unfortunately do to the high visibility we started to get
> emails from users and the press about the application no longer working.
>
> Has anyone experienced this before and/or can you give guidance on how to
> diagnose or prevent this?
>
> Here are some config settings:
> CentOS 5.7
> Java 1.6
> TDS 4.3.17
> only WMS is enabled
> Java -Xmx set to 8Gb (currently taking 5.3, the dataset is 600 Gb of
> 30-arcsecond grids for the continental US, 3.4 Gb per file)
> For better or worse we are configured to use 2 instances of TDS to keep
> the catalogs and configuration isolated. I’m not sure if this matters, but
> I didn’t want to omit it. Since it is a live server I can’t easily change
> to the preferred proxy configuration.
>
> I am trying not to panic yet. However, if the server goes unresponsive
> again, staying calm may no longer be an option.
>
> Jay Alder
> US Geological Survey
> Oregon State University
> 104 COAS Admin Building
> Office Burt Hall 166
> http://ceoas.oregonstate.edu/profile/alder/
>
>
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--
Gerry Creager
NSSL/CIMMS
405.325.6371
++++++++++++++++++++++
“Big whorls have little whorls,
That feed on their velocity;
And little whorls have lesser whorls,
And so on to viscosity.”
Lewis Fry Richardson (1881-1953)
