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P3700 wear info

idata
Esteemed Contributor III

i neet to monitor wearout info of my drives.

with my X25-E and S3700 i simply check SMART values like Media_Wearout_Indicator, Power_On_Hours and Host_Writes_32MiB

now with P3700 the closest i can find is "Wear Leveling Count" and "Timed Workload - Media Wear"

no info about how many hours the drive is at work and how many bytes have been written.

i'm using latest ssd toolbox and datacenter tool (isdct show -sensor -intelssd)

where did you hide that two indicators?

and also what's the difference between those two wear indicators? which one should i watch for?

8 REPLIES 8

jbenavides
Valued Contributor II

Timed Workload and Wear Leveling Count are not the same. You can review the details and description for each in the Product Specifications document I linked before.

Timed workload - Media Wear can be used by system administrator's to measure the media wear induced on the drive under a specific workload, this may help estimate the expected lifetime of a drive under system-specific conditions.

Another SMART attribute you may find useful to monitor drive wear is "Percentage Used Estimate", this value increases as the drive is used over time. A value of 100 indicates that the estimated endurance of the device has been consumed.

Wear Leveling Count can also provide endurance information, based on the rated life cycles.

In regards to "Host Bytes Written" and "NAND Bytes Written", they refer to the amount of bytes writes requested by the host, and the actual amount of bytes writen to NAND memory chips. These values can be different because of the tasks run by the controller and the technologies it uses to handle the data.

The full list of SMART attributes and their description is found in the http://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/ssd-dc-p3700-spec... Intel® SSD DC P3700 Series - Product Specification.

Also, you might want to check the Intel® SSD Data Center Tool User's Guide, it has all the commands and options supported by ISDCT. The guide can be obtained in the page: https://downloadcenter.intel.com/download/23931/Intel-Solid-State-Drive-Data-Center-Tool Download Intel® Solid-State Drive Data Center Tool

idata
Esteemed Contributor III

thanks. looks like all the info i want is in the "Table 18 SMART Attributes (Log Identifier 02h)"

will check those on my drives later

idata
Esteemed Contributor III

have to lift up this thread again.

so "Host Bytes Written" is how many 32bytes blocks have been requested to write by operating system.

and "NAND Bytes Written" is the same 32b blocks that was actually written to ssd?

so when saying 400gb p3700 write endurance is 7300Gb this means 7300Gb of "NAND Bytes Written", right?

i've checked few of my new drives and there i see "nand" is 3+ times higher than "host".

is that normal? because then looks like actual, real life endurance is 3 times lower than it stated in pdf's (http://www.mouser.com/ds/2/612/ssd-dc-p3700-spec-769407.pdf http://www.mouser.com/ds/2/612/ssd-dc-p3700-spec-769407.pdf )

idata
Esteemed Contributor III

just did a quick test.

first i've copied 11.4gb file to tmpfs (memory)

checked my smart info:

nand: 10203 = 326.496gb

host: 3360 = 107.520gb

then i've copied that ram file to ssd and got:

nand: 10572 = 338.304gb

host: 3716 = 118.912gb

so that operation took:

11.392gb of host writes and 11.808 of nand writes.

i have no clue why i have currently nand writes 3 times higher than host writes, maybe they become closer after few months of use.

i still want to know which of those values i have to watch and compare to stated lifetime endurance (7.3Pb for 400gb version)?

how those 7.3Pb was calculated in your tests?