Recently I saw some unexplained LUN trespasses on an EMC VNX that is used in a vSphere 5 environment where we use VAAI.
Since we use pools on the VNX, it is advised to keep a LUN on the owning SP, to prevent unnecessary traffic over the internal bus between SPA and SPB. EMC says:
Avoid trespassing pool LUNs. Trespassing the pool LUNs to another SP may adversely affect performance. After a pool LUN trespass, a pool LUNs private information remains under control of the original owning SP. This will cause the trespassed LUNs I/Os to continue to be handled by the original owning SP. When this happens both SPs being used in handling the I/Os. Involving both SPs in an I/O increases the time used to complete an I/O. Continue reading
A while ago I decided to purchase an official wildcard ssl certificate to use in my VMware demo/lab environment. Purchasing the certificate turned out to be the easy part. The next step was installing the certificate on different VMware products, like vCenter (which includes Update Manager and some web services nowadays), View connection servers, vCenter operations, and Zimbra.
I went trough the official documentation, and learned very quickly this was not as simple as I had expected. All products have very specific installation instructions, and some are better then others. Continue reading
After upgrading an environment from ESX5 to ESX5U1, I noticed syslog stopped working. Since ESXi by default does not keep log messages across reboots, it is a must to either specify a syslog server to collect the log files, or set the log directory to a shared datastore.
In this environment I used syslog to log all messages from the ESX hosts to a central syslog server.
When checking the syslog server after the upgrade, I noticed there where no more log messages arriving at the syslog server, and confirmed there used to be log messages just prior to the upgrade. Continue reading