Changing the zone path of a pre-existing zone
So, the hostname of one of our zones changed, and we create ZFS file systems for the zones using / Easy enough of a fix... So now that we've changed the zone name, I also wanted to update the ZFS file system to reflect the new hostname... Easy enough. Lets boot the zone…
$ read more →Built-in memory testing in the Linux 2.6.26 kernel
I have been using memtest86 and a custom built hardware testing image based on OpenSolaris, FMA and sun VTS for quite some time, and have had fantastic success with them. I just learned that the Linux kernel developers added built-in memory testing support to the Linux 2.6.26 kernel: "Memtest is a commonly used tool for checking your memory. In 2.6.26 Linux is including his own in-kernel memory tester. The goal is not to replace memtest, in fact this tester is much simpler and less capable than memtest, but it's handy to have a built-in memory tester on every kernel…
$ read more →Understanding memory usage on Linux hosts just got easier
While looking at the features that were added to the Linxu 2.6.20.X kernels, I came across this gem on the kernelnewbies website: "Measuring how much memory processes are using is more difficult than it looks, specially when processes are sharing the memory used. Features like /proc/$PID/smaps (added in 2.6.14) help, but it has not been enough. 2.6.25 adds new statistics to make this task easier. A new /proc/$PID/pagemaps file is added for each process…
$ read more →Fixing Solaris Cluster device ID (DID) mismatches
I had to replace a disk in one of my cluster nodes, and was greeted with the following message once the disk was swapped and I checked the devices for consistency: cldevice: (C894318) Device ID "snode2:/dev/rdsk/c1t0d0" does not match physical device ID for "d5". Warning: Device "snode2:/dev/rdsk/c1t0d0" might have been replaced. To fix this issue, I used the cldevice utilities repair option: Once the repair operation updated the devids, cldevice ran cleanly: Niiiiiiiiice!
$ read more →Building clusters with shared disk using VMWare server 2.0
I have a couple of lab machines that are running VMWare server 2.X under 64-bit CentOS 5.2. VMWare server has a cool feature where you can create "clusters in a box." The cluster in a box feature allows you to share a virtual disk between more than one virtual machine, and since it support SCSI persistent reservations, you can truly simulate a real cluster. I have used this to deploy Oracle RAC, Solaris Cluster and Redhat Cluster server in my lab environment. Based on the cluster in a box documentation on the VMWare website, sharing a disk between multiple nodes can be achieved by creating a virtual disk, and then importing that disk into each virtual machine…
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