Archive
Posts from 2012
Summarizing system call activity on Linux systems
Linux has a guadzillion debugging utilities available. One of my favorite tools for debugging problems is strace, which allows you to observe the system calls a process is making in realtime. Strace also has a "-c" option to summarize system call activity: The output contains the percentage of time spent in each system call, the total time in seconds, the microseconds per call, the total number of calls, a count of the number of errors and the type of system call that was made. This output has numerous uses, and is a great way to observe how a process is interacting with the kernel…
$ read more →Installing OpenSSH on an AIX 7.1 server
I'm pretty new to AIX, and I'm learning all about its idiosyncrasies. One thing I still don't understang is why SSH isn't installed by default. The packages are located on the AIX 7 Volume 1 of 2 DVD, but for some reason the installer doesn't feel the need to make sshd available to the system at install time. For those who care about security, the following steps will get SSH installed and operational on your AIX 7.1 server: First, mount the "AIX 7 Volume 1 of 2" DVD in your drive (NIM installs aren't covered here) and mount it up: Once you mount the DVD you will need to change to the package directory: From there you can install the openssh and openssl packages: This will install the packages and enable the SSH service…
$ read more →Scalable storage for QEMU/KVM
While reading up on various scalable file systems I came across the sheepdog project. For those new to sheepdog, their website describes it as: "Sheepdog is a distributed storage system for QEMU/KVM. It provides highly available block level storage volumes that can be attached to QEMU/KVM virtual machines. Sheepdog scales to several hundreds nodes, and supports advanced volume management features such as snapshot, cloning, and thin provisioning." This looks really cool, and I'm hoping to play around with it this weekend…
$ read more →Visualizing syslog data with LogAnalyzer and rsyslog-mysql
I recently discussed setting up rsyslog to write syslog data to a MySQL databas e. Once you get this set up, you can start writing SQL statements to view the data in various ways. The next logical step is visualizing your data, and that's where LogAnalyzer comes in. LogAnalyzer is a PHP application that can be used to visualize syslog data…
$ read more →Configuring a user to use the bash shell on an AIX server
I previously wrote about my experience installing bash on my AIX hosts. After I installed the package I wanted to make bash my default shell. I fired up usermod but was greeted with the following error: AIX contains a list of valid shells in /etc/security/login.cfg, and bash is not in that list by default: Once I appended "/usr/bin/bash" to the end of the "shells" line usermod worked without a hitch: Rock and roll!!
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