PDL error msg write failure

[Mark Perschbacher]

We are running ver. 5.6 R2 on a Win2003 server, and have experienced a PDL error several times now that has run amok and eaten up many GB’s of log space.  We are using mlp_tcp.pdl for the outbound thread.  The error is

write of 2230 bytes failed: unknown error

PDL signaled exception: code 1, msg write failure.

Any one else having this same issue?

Topic

[Simone Heckmann]

Hi Mark,

I guess, that’s what happens when the receiving end of this communication closes the socket and cloverleaf – for some reason beyond my ken – doesn’t realize that. The connection still shows ‘up’ in the NetworkMonitor and the next time Cloverleaf tries to write into the socket, the ‘write failed’ error returns. From then on, Cloverleaf retries approximately twice every nanosecond, resulting in rather unhandy logfiles and lots of CPU consumption.

After restarting the thread everything’s back to normal…

Best way to solve this in my experience has been to keep the receiving application from closing it’s socket after receiving a message.

Any attempts on my side to automatically restart the thread using alerts have resulted in a frozen MonitorDaemon because the Thread responds too slow to the Daemon’s command  😕

That’s a tough one to debug since the problem isn’t really reproduceable…

Good luck,

Simone

[Rob Abbott]

Hi all, I believe this is fixed in 5.7 rev2 and 5.8.  From 5.7rev2 release notes:

Quote:

Issue: PDL error fills up the disk space in the VPN environment (6248)

Description

Errors occur when using TCP-MLP through VPN. The same error echo in the process log until the process panic because the logs filled up the disk.

For example:

[pdl :PDL :ERR /0: bno31bb_out:01/27/2009 17:04:44] read returned error

0 (Success)

When this error occurs, the thread stays in an UP status because there was not a graceful shutdown from the VPN.

This error no longer occurs. A sleep interval has been added for retrying the connection, and the engine will now detect if there is an error and put the thread in error state.

Rob Abbott
Cloverleaf Emeritus

[Mark Perschbacher]

That certainly sounds like the issue, thanks Rob

[Author]

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