Configuring VMware vSphere for best performance

Below are a couple of things to consider when configuring your VM’s for best performance.

  • Disconnect any devices that your VM’s don’t use – This removes any unnecessary kernel processing.
  • Always use Thick Provision Eager Zero disks.
  • Use multiple NIC’s and team them together.
  • Use Round Robin on NIC’s with IP Hash for your load balancing.
  • Use Software iSCSI with Jumbo Frames (Unless you HBA card support Jumbo Frames). If you don’t use Jumbo Frames then an HBA card could provide 150% better performance – This is due to the TOE (TCP Offload Engine) function on the cards. But if your HBA card does not support Jumbo Frames then use Software iSCSI with Jumbo Frames.
  • Set Jumbo Frames to 9000. You would need to set this on all interfaces (VM NIC’s on host, switches and SAN).
  • Put VM’s on different LUN’s (1 LUN = 1 I/O queue).
  • Set block sizes according to application requirements. Eg: for a MS SQL server you would set the block size on the SAN (RAID where SQL VM will reside) to 64k and also format the VM guest OS partitions with 64k block sizes.
  • Optimize VM’s according to NUMA.
  • Enable large memory pages on critical production servers (Inside guest OS). But don’t do this on all servers otherwise they can’t share memory pages.

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