VMware: Read Locality in Hybrid 2 Node Virtual SAN
A question was asked the other day about the performance behavior a virtual machine after a vMotion on a 2 Node Virtual SAN configuration. The question basically was:
“Should there be a degradation in read performance after a virtual machine is vMotioned to the alternate host in a Hybrid 2 Node Virtual SAN configuration?”
During normal operations, the user was seeing a large number of IOPS on a read workload, but when moving the virtual machine to the alternate host, the read IOPS dropped by a large amount. After some time, the performance returned to normal. When they vMotioned the virtual machine back to the original host, they experienced the same degradation of read performance. Again, after some time, the performance returned to normal.
In fact, this is the correct out-of-the-box behavior for 2 Node Virtual SAN configurations. To understand why, it is important to know how write and read operations behave in 2 Node Virtual SAN configurations. This post covers Virtual SAN 6.1 and 6.2.
Read the entire article here, Read Locality in Hybrid 2 Node Virtual SAN
via the fine folks at VMware!