VMworld 2014/Performance best practices to run virtualized applications on Virtual SAN

Benchmarking VSAN 101:
 * Give time for SSD cache to warm up
 * Monitor performance metrics on each host
 * Look out for odd situations:
 * read cache hit rate when working set doesn't fit in SSD
 * de-staging performance for "write" workloads
 * distribution of vmdks across cluster
 * SSD and MD (magnetic disk) IOPS and bandwidth
 * spikes in latency due to sudden MD accesses
 * CPU bottlenecks

Tools:
 * VSAN Observer (KB 2064240)
 * Esxtop
 * Ruby vSphere Console (RVC) - fling

VSAN Observer:
 * Check the Read Cache (RC) Hit Rate

Configuring for Performance:
 * SSD very important - check both read and write performance
 * Controllers - queue depth and on-board cache
 * MD (Magnetic Disk) - faster disk helps with de-staging
 * VSAN Hardware guidance (doc? site?)
 * Sizing of SSD to MD ration, must hold as much working set as possible
 * Stripe width - go higher than 1 if % of VMs IO served from read cache is low

Microbenchmarks show:
 * excellent read performance
 * mixed read/write workload performance depends on working set size and performance of SSDs/MDs