====== Using Zimbra in a Virtual Machine ======

http://wiki.zimbra.com/wiki/Performance_Recommendations_for_Virtualizing_Zimbra_with_VMware_vSphere

**iSCSI**: https://marksallee.wordpress.com/2010/03/16/zimbra-mail-on-xenserver-virtual-machines-iscsi/

**Optimization**: http://wiki.zimbra.com/wiki/Performance_Tuning_Guidelines_for_Large_Deployments#JVM_Options

**More Optimization**: http://www.zoobey.com/index.php/2-rough/726-zimbra-optimization-part1

===== Memory =====

  * NUMA - Size VM RAM no larger than RAM local to a single physical CPU
  * Don't use memory ballooning on Zimbra VM
  * 4GB RAM minimum - swaps a little
  * 6GB RAM for a busier server or a VM

===== CPU =====

  * Zimbra is not a CPU-bound workload
    * 2 vCPUs are generally recommended
    * Don't under-commit, over-commit or over-utilize vCPUs
    * Reduce vCPUs until peak usage points reach 60% utilization
  * Periods of high, sustained CPU utilization can be caused by insufficient RAM or disk I/O wait
    * Try increasing the memory allocated to the VM

===== Disk =====

  * In general, Zimbra is an I/O bound workload
  * Optimize your storage in the normal ways
  * iSCSI is recommended over NFS