Disabling Quotas on a ReadyNAS Ultra NAS

If you have a ReadyNAS Ultra you may want to disable quotas in order to eliminate some issues.  I’ve experienced issues myself where CIFS copies would fail due to the filesystem being out of space even though quotas are set insanely high and the ReadyNAS interface is reporting plenty of space left on the device.  …

PHP Fatal error: Call to undefined function posix_getpwuid()

I found that this error appears rather often online but almost no one has any idea why it would come up.  I found this error myself today while doing an install of FreePBX on Fedora 14.  My full error was: Checking user..PHP Fatal error:  Call to undefined function posix_getpwuid() in /usr/src/freepbx-2.8.1/install_amp on line 728 This …

Latency and Software Developers

I was recently having a conversation where someone asked me to compare real time and low latency Linux kernels.  I used the phrase “real time is the enemy of low latency.”  This caught some attention and I was asked to explain what I meant.  In order to accommodate the needs of real time processing we need to …

Testing Socket Connections Programmatically

Often we have to use “telnet remotehost.somewhere.com 80” to test if a remote socket connection can be established.  This is fine for one time tests but can be a problem when it comes time to test a number of connections – especially if we want to test them programmatically from a script.  Perl to the …

Windows Server 2008 R2 on Xen

Having poked around in the forums I have found that no one seems to believe, at least not at the time of this writing, that Windows Server 2008 R2 can be deployed on Xen or, if it can, that you cannot do so using the Xen package available in Red Hat Linux 5.  I am …