VSAN-Troubleshooting-Reference-Manual

Diagnostics and Troubleshooting Reference Manual – Virtual SAN
Flash considerations in version 5.5
While the focus in this scenario has been on a PCI-E flash device, there is of course
full support for Solid State Disks on Virtual SAN. Of particular interest is the class of
flash device. There are two classes, performance and endurance. Performance is
measured in the number of writes per second, whereas endurance, in Virtual SAN
5.5, is measured in full disk writes per day (DWPD).
When deciding which class of flash device to use with your Virtual SAN deployment,
these are the two features that require serious consideration.
Performance classes are as follows:
Class
Writes per second
B 5,000 – 10,000
C 10,000 – 20,000
D 20,000 – 30,000
E 30,000+
Endurance classes for Virtual SAN 5.5 are as follows:
Class
Disk Writes Per Day
A 1-5
B 5-10
C 10-20
D 20+
However for Virtual SAN 6.0, endurance is now considered using the metric TBW, or
Terabytes Written.
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