Broken Pipe Errors

[itwasntme]

I looked at the Apache error log on my problem-child VPS this morning and saw a bunch of errors like this:

[Mon Nov 05 11:15:24 2007] [info] [client 127.0.0.1] (32)Broken pipe: core_output_filter: writing data to the network

According to this post on cPanel's Forums a fix is to add the following to Apache's config file httpd.conf:

EnableSendfile Off

Apache's web site has this to say about EnableSendfile:

This directive controls whether httpd may use the sendfile support from the kernel to transmit file contents to the client. By default, when the handling of a request requires no access to the data within a file -- for example, when delivering a static file -- Apache uses sendfile to deliver the file contents without ever reading the file if the OS supports it.

This sendfile mechanism avoids separate read and send operations, and buffer allocations. But on some platforms or within some filesystems, it is better to disable this feature to avoid operational problems:

* Some platforms may have broken sendfile support that the build system did not detect, especially if the binaries were built on another box and moved to such a machine with broken sendfile support.
* On Linux the use of sendfile triggers TCP-checksum offloading bugs on certain networking cards when using IPv6.
* With a network-mounted DocumentRoot (e.g., NFS or SMB), the kernel may be unable to serve the network file through its own cache.

For server configurations that are vulnerable to these problems, you should disable this feature by specifying:

 EnableSendfile Off

For NFS or SMB mounted files, this feature may be disabled explicitly for the offending files by specifying:

  
     EnableSendfile Off  

Based on that information, it sounds like disabling Sendfile would be a bad thing for this server in that it would presumably increase server load.

I looked in my /usr/local/apache/conf/httpd.conf and couldn't find "EnableSendfile" in there.

I'm over my head (again). Can someone who knows more about Apache and HIC's setup tell me what to do about this?

[lnxcode]

You can try to disable it and see where it goes. However, to be honest, I've never played with this feature (never had a reason to)... but I think its worth a shot. Worst comes to worst you can do this:

cd /usr/local/apache/conf/ &&
cp httpd.conf httpd.conf.bkup

Once you've done the above edit the httpd.conf and test it out. In cron you can set:

*/45 * * * * mv httpd.conf httpd.conf.updated && mv httpd.conf.bkup httpd.conf

So every 45 mins it will replace the updated conf with the old conf (before you updated it).