vSphere Storage - ESXi 5.1 - Documentation - VMware

Best Practices for SSD Devices
Follow these best practices when you use SSD devices in vSphere environment.
n Use datastores that are created on SSD storage devices to allocate space for ESXi host cache. For more
information see the vSphere Resource Management documentation.
n Make sure to use the latest firmware with SSD devices. Frequently check with your storage vendors for
any updates.
n Carefully monitor how intensively you use the SSD device and calculate its estimated lifetime. The lifetime
expectancy depends on how actively you continue to use the SSD device.
Estimate SSD Lifetime
When working with SSDs, monitor how actively you use them and calculate their estimated lifetime.
Typically, storage vendors provide reliable lifetime estimates for an SSD under ideal conditions. For example,
a vendor might guarantee a lifetime of 5 years under the condition of 20GB writes per day. However, the more
realistic life expectancy of the SSD will depend on how many writes per day your host actually generates.
Follow these steps to calculate the lifetime of the SSD.
Procedure
1 Obtain the number of writes on the SSD by running the
esxcli storage core device stats get -d=device_ID command.
The Write Operations item in the output shows the number. You can average this number over a period
of time.
2 Estimate lifetime of your SSD by using the following formula:
Chapter 16 Solid State Disks Enablement
vendor provided number of writes per day times vendor provided life span divided by actual average number of
writes per day
For example, if your vendor guarantees a lifetime of 5 years under the condition of 20GB writes per day,
and the actual number of writes per day is 30GB, the life span of your SSD will be approximately 3.3 years.
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