Archive: Posts

Steps to Run Iometer in a VMware VM?

Iometer is a great storage IO testing tool. It is easy to use, flexible, accurate, and free. Below are steps to run Iometer from within a Windows VM running on VMware. Step1: Install the older 2006.07.27 edition. Don’t use the latest 1.1.0 edition which has bugs. Download link is here. Change only the parameters listed below, keep all else default. Step 2: After you install Iometer, run it with Windows ‘run as Administrator’ option. Each ‘Worker’ (screenshot below) is a process (or...

To Improve CEPH performance for VMware, Install SSDs in VMware hosts, NOT OSD hosts.

SSDs deployed for caching in CEPH OSD servers are not very effective. The problem lies not in the SSDs, but because they are deployed at a point in the IO path that is downstream (in relation to VMs that run user applications) of where the IO bottleneck is. This post looks at this performance shortcoming of CEPH and its solution. There are two options for improving the performance of CEPH. Option 1 is to deploy SSDs in CEPH OSD servers for journaling (write caching) and read caching. Option...