MENU

TBW from SSDs with S.M.A.R.T Values in ESXi

Posted by Oksana Zybinskaya on May 23, 2016
Share on Facebook0Share on Google+0Share on LinkedIn0Share on Reddit0Tweet about this on Twitter0
No ratings yet.

Solid-State-Drives are becoming widely implemented in ESXi hosts for caching (vFlash Read Cache, PernixData FVP), Virtual SAN or plain Datastores. Unfortunately, SSDs have  limited lifetime per cell. Its value may range from 1.000 times in consumer TLC SSDs up to 100.000 times in enterprise SLC based SSDs. Lifetime can be estimated by device TBW parameters provided by vendor in its specification, It describes how many Terabytes can be written to the entire device, until the warranty expires.smartctl_in_esxi

As VMWare does not provide convenient and easy way to read RAW S.M.A.R.T values on ESXi hosts, a ported version of smartctl has been created, which is part of smartmontools to ESXi.

Below there is an example of an ESXi Host report without smartctl. The device analyzed is a Samsung SSD 850 EVO M.2 250GB used as a local Datastore. Warranty for this SSD is 75TBW.

ESXCLI can display S.M.A.R.T stats with
esxcli storage core device smart get -d [device]

The next table shows the stats provided by ESXCLI, which are a bit more verbose.

ESXi keeps track of all read and write operations to the disk, but the counters get reset when ESXi is rebooted.

And here is the report by smartctl:

In the SMART Attributes section, there is a Total_LBAs_Written value (ID #241). In order to get Terabytes, we need to multiply this value with the sector size (512 bytes) and divide by 1099511627776 (1024^4).

                                                Total_LBAs_Written * Sector Size / 1024^4 = TBW

                                      6343034492 * 512 / 1099511627776 = 2.95 TBW

That gives us 3 of 75 TBW. Taking into consideration the parameter Power_On_Hours (SMART ID #9), which tells us that the device has been in use for about 200 days, we may prognose that this SSD will last for the next 13 years.

The smartctl can be obtained from here:

http://www.virten.net/files/smartctl-6.6-4321.x86_64.vib

Note: The use of this VIB is totally unsupported, proceed at your own risk. Tested with ESXi only.

This is the review of an article.

Source: www.virten.net

Related materials:

Views All Time
3
Views Today
9

Please rate this

Return to all posts

NUMA and Cluster-on-die
Rename VM network adapter automatically from Virtual Machine Manager 2016
The following two tabs change content below.
Oksana Zybinskaya
Oksana Zybinskaya
PR-manager in StarWind. In touch with virtualization world, may know stuff you are interested in.