100% CPU use

I needed to restart my mongrel cluster today (updated a Rails
controller). And my mongrels didn’t really come back up. They bind the
port but don’t respond to any requests. I can’t find any log file that
has useful information. These were running fine until I tried the
restart. And I have not changed any software versions in a month. (And
yes, I tried rolling back the controller change.)

Where can I find more information about why this isn’t responding
anymore?

Ruby: ruby 1.8.5 (2006-08-25) [i386-linux]
Mongrel: mongrel (1.0.1)
Rails: 1.2.3

The only thing in the mongrel log is:

** Starting Mongrel listening at 192.168.19.116:3000
** Changing group to staff.
** Changing user to mongrel.
** Loading additional MIME types from
** /srv/config/mongrel/extra_mime_types.yml
** Starting Rails with production environment…

Wget connects and then hangs with:
HTTP request sent, awaiting response…

Top shows:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2305 mongrel 25 0 38404 19m 4192 R 50.7 7.7 6:20.55
mongrel_rails
2308 mongrel 25 0 38396 19m 4188 R 49.3 7.7 6:26.68
mongrel_rails


Cynthia K.

I hate mailing list threads that post a problem but not the solution,
so I thought I would write back to say that the issue appears to have
been some strangness with the Oracle libraries. Looking at our
snapshotted volume, the libraries had not changed since installing
about 2 months ago. However, for reasons that are still unclear, any
attempt to connect to Oracle from that box looked at the sqlnet.ora
file and then went into a strange polling state that consumed all
available CPU. After getting some hint of this from stracing the hung
mongrel process, we were able to reproduce the same problem using just
sqlplus. So this was NOT a mongrel nor a rails issue. Perhaps even
more mystriously, rebooting the server (a Xen VM running RHEL 5) fixed
the problem. Thanks to the folks here and on the mongrel IRC room for
all their suggestions on how to track this down.


Cynthia K.

Cynthia,

Thank you VERY much for the followup.

~Wayne.

I needed to restart my mongrel cluster today (updated a Rails
controller). And my mongrels didn’t really come back up. They bind the
port but don’t respond to any requests. I can’t find any log file that
has useful information. These were running fine until I tried the
restart. And I have not changed any software versions in a month. (And
yes, I tried rolling back the controller change.)

I had this problem on os x recently–if mongrel has been running
‘awhile’ (i.e. answered a few requests), then i hit ctrl-c on it, it
uses 100% cpu and never terminates. Very odd. Might be a ruby bug.
Any thoughts?
(this with mysql, leopard, mongrel 1.1.3).
thanks.
-Roger

On Feb 4, 2008 2:38 PM, Roger P. [email protected] wrote:

uses 100% cpu and never terminates. Very odd. Might be a ruby bug.
Any thoughts?
(this with mysql, leopard, mongrel 1.1.3).
thanks.
-Roger

I also have experienced this with Rails but not Merb so I’m guessing
that is
where the issue lie.

~Wayne

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