Veni, vidi, VAAI
Recently, I was asked to investigate a performance issue on a VMware environment. Configuration of the ESXI hosts and storage was just finished and engineers were busy deploying Virtual Machines from a Template. The main issue was; “Actual time to deploy a VM is much more than expected”.
The Environment consists of the following components:
- Dell Equallogic PS4100X, with 24 x 300 GB 10K SAS drives in RAID-50 config;
- Storage switches, two Dell PowerConnect 6224 stacked;
- ESXi servers, three Dell R815, 32 GB and 6 NICs;
- VMware vSphere 5 Enterprise Edition.
First step was to check the configuration of the components. Configuration of the servers and storage was according to Dell’s “Configuring VMware vSphere Software iSCSI with Dell EqualLogic PS Series Storage”.
At first glance, everything seems to be OK, so now it is time to do some testing and see with my own eyes what is going on. I started the deployment of a template of a VM, configured with a 60 GB virtual disk on the same ESXI server, at the same time logged in on the console and started esxtop and switched to the “disk adapter” view. During the deployment, the iSCSI software adapter (vmhba40) showed a steady 60 MB/s read (MBREAS/s) and 60 MB/s write (MBWRTN/s). The Total Latency (GAVG/cmd) is 4.10 ms., which is fine (as Mr. Eric Sloof explained in an Advanced Troubleshooting presentation).