Reading SMART data on an SSD ?

[Rob_B]

Hi folks,

I'm soon getting an SSD and just wanted to check something, should I be worried about these SMART results as I am unsure how to read them/if SMART is even useful on an SSD and a google was inconclusive, any help?!
It's the prefail values that I'm not so sure about?

Thanks for any help!!

Rob
----------------

tmp$ sudo smartctl -a /dev/sdd
smartctl 5.43 2012-06-30 r3573 [x86_64-linux-3.2.0-31-generic] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF INFORMATION SECTION ===
Model Family: SandForce Driven SSDs
Device Model: OCZ-AGILITY3
Serial Number: OCZ-22VC8SK5OIBWSB81
LU WWN Device Id: 5 e83a97 f18be706d
Firmware Version: 2.22
User Capacity: 120,034,123,776 bytes [120 GB]
Sector Size: 512 bytes logical/physical
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: ACS-2 revision 3
Local Time is: Thu Oct 11 16:56:03 2012 BST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status: (0x00) Offline data collection activity
was never started.
Auto Offline Data Collection: Disabled.
Self-test execution status: ( 0) The previous self-test routine completed
without error or no self-test has ever
been run.
Total time to complete Offline
data collection: ( 0) seconds.
Offline data collection
capabilities: (0x7b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x01) Error logging supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 1) minutes.
Extended self-test routine
recommended polling time: ( 48) minutes.
Conveyance self-test routine
recommended polling time: ( 2) minutes.
SCT capabilities: (0x0021) SCT Status supported.
SCT Data Table supported.

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x000f 120 120 050 Pre-fail Always - 0/0
5 Retired_Block_Count 0x0033 100 100 003 Pre-fail Always - 0
9 Power_On_Hours_and_Msec 0x0032 000 000 000 Old_age Always - 3442h+45m+35.920s
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 178
171 Program_Fail_Count 0x0032 000 000 000 Old_age Always - 0
172 Erase_Fail_Count 0x0032 000 000 000 Old_age Always - 0
174 Unexpect_Power_Loss_Ct 0x0030 000 000 000 Old_age Offline - 39
177 Wear_Range_Delta 0x0000 000 000 000 Old_age Offline - 5
181 Program_Fail_Count 0x0032 000 000 000 Old_age Always - 0
182 Erase_Fail_Count 0x0032 000 000 000 Old_age Always - 0
187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0
194 Temperature_Celsius 0x0022 128 129 000 Old_age Always - 128 (0 127 0 129 0)
195 ECC_Uncorr_Error_Count 0x001c 100 100 000 Old_age Offline - 0/0
196 Reallocated_Event_Count 0x0033 100 100 003 Pre-fail Always - 0
201 Unc_Soft_Read_Err_Rate 0x001c 100 100 000 Old_age Offline - 0/0
204 Soft_ECC_Correct_Rate 0x001c 100 100 000 Old_age Offline - 0/0
230 Life_Curve_Status 0x0013 100 100 000 Pre-fail Always - 100
231 SSD_Life_Left 0x0013 100 100 010 Pre-fail Always - 0
233 SandForce_Internal 0x0000 000 000 000 Old_age Offline - 4310
234 SandForce_Internal 0x0032 000 000 000 Old_age Always - 4832
241 Lifetime_Writes_GiB 0x0032 000 000 000 Old_age Always - 4832
242 Lifetime_Reads_GiB 0x0032 000 000 000 Old_age Always - 5028

SMART Error Log not supported
SMART Self-test Log not supported
SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

[DanceswithUnix]

Looks pretty much perfect to me, going by these descriptions from another Sandforce SSD:

http://media.kingston.com/support/do..._attribute.pdf

Can't see any errors that it has had to correct, and according to stat 231 you have 100% of drive life left so have hardly used its program/erase cycle count. As you seem to have written 4.8TB to a 120GB drive I can only assume the data compresses well

Edit to add: Actually thats 4800/120 = 40 times the drive capacity written, so should be less than 40 cycles for the drive. If the flash can do 10000 PE cycles, then you have quite a lot longer to go, you are (40/10000)*100= 0.4% through the drives life. I am guessing the 10K cycles count btw, I have no idea what characteristics the flash in these drives have, but it fits with what the drive is reporting.

[Rob_B]

Nice one, thanks for that

I saw those words and thought oh-oh but seems all is ok