[kwlug-disc] SMART for SSDs
Khalid Baheyeldin
kb at 2bits.com
Wed Jul 29 14:44:38 EDT 2015
Thanks Lori.
The drive is an OCZ Vertex4, 256GB.
On Wed, Jul 29, 2015 at 1:37 PM, L.D. Paniak <ldpaniak at fourpisolutions.com>
wrote:
> With less than 800 power-on hours, this drive would have had to seen
> rather aggressive continuous writes to reach the end of its endurance.
> I doubt you have anything to worry about here.
> Raw read error rate is generally not useful info for end users.
> Reallocated sector count is probably the attribute to watch on this drive.
>
> What make/model is this SSD? Hard to tell if lifetime writes are LBAs or
> bytes.
> Maybe write 1MB of non-compressible file to the drive and see how this
> value changes. Either way you should be OK.
>
> The analogous information for the Samsung 840 Pro in my laptop is:
> Vendor Specific SMART Attributes with Thresholds:
> ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED
> WHEN_FAILED RAW_VALUE
> 5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail
> Always - 0
> 9 Power_On_Hours 0x0032 099 099 000 Old_age
> Always - 4639
> 12 Power_Cycle_Count 0x0032 098 098 000 Old_age
> Always - 1300
> 177 Wear_Leveling_Count 0x0013 099 099 000 Pre-fail
> Always - 3
> 179 Used_Rsvd_Blk_Cnt_Tot 0x0013 100 100 010 Pre-fail
> Always - 0
> 181 Program_Fail_Cnt_Total 0x0032 100 100 010 Old_age
> Always - 0
> 182 Erase_Fail_Count_Total 0x0032 100 100 010 Old_age
> Always - 0
> 183 Runtime_Bad_Block 0x0013 100 100 010 Pre-fail
> Always - 0
> 187 Reported_Uncorrect 0x0032 100 100 000 Old_age
> Always - 0
> 190 Airflow_Temperature_Cel 0x0032 070 055 000 Old_age
> Always - 30
> 195 Hardware_ECC_Recovered 0x001a 200 200 000 Old_age
> Always - 0
> 199 UDMA_CRC_Error_Count 0x003e 100 100 000 Old_age
> Always - 0
> 235 Unknown_Attribute 0x0012 099 099 000 Old_age
> Always - 84
> 241 Total_LBAs_Written 0x0032 099 099 000 Old_age
> Always - 4381884472
>
>
> Here LBAs are 512bytes. Attribute 241 says I have written
> 4381884472*512B = 2.2x10^12B = 2.2TB
> I would expect to get 100TB of writes on the drive before starting to
> worry.
> The drive is rated for 300TB write.
>
> Tests of this kind of drive have gotten over 2.4PB of writes in before the
> drive quit:
>
> http://techreport.com/review/27909/the-ssd-endurance-experiment-theyre-all-dead
>
>
>
> On 07/29/2015 12:52 PM, Khalid Baheyeldin wrote:
>
> So, I had an SSD lying around for a couple of years (long story, bought
> to benchmark against spinning rust disks for a client project). My laptop
> disk died 1.5 months ago, and when checking SMART values for it, it was not
> good.
>
> Therefore, I decided to put the SSD drive in the laptop, and copy the
> spinning drive to it. I blogged on the details of how to do that separately.
>
> When I run SMART on the SSD drives (smartctl --all /dev/sda), I get the
> following table:
>
> For those who have been using SSDs for a while, my question is: should I
> be worried about lines with ID 1 and 233?
>
> Vendor Specific SMART Attributes with Thresholds:
> ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED
> WHEN_FAILED RAW_VALUE
> 1 Raw_Read_Error_Rate 0x0000 006 000 000 Old_age
> Offline - 6
> 3 Spin_Up_Time 0x0000 100 100 000 Old_age
> Offline - 0
> 4 Start_Stop_Count 0x0000 100 100 000 Old_age
> Offline - 0
> 5 Reallocated_Sector_Ct 0x0000 100 100 000 Old_age
> Offline - 0
> 9 Power_On_Hours 0x0000 100 100 000 Old_age
> Offline - 796
> 12 Power_Cycle_Count 0x0000 100 100 000 Old_age
> Offline - 74
> 232 Lifetime_Writes 0x0000 100 100 000 Old_age
> Offline - 3033270496
> 233 Media_Wearout_Indicator 0x0000 100 000 000 Old_age
> Offline - 100
>
> --
> Khalid M. Baheyeldin
> 2bits.com, Inc.
> Fast Reliable Drupal
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> wrong." -- H.L. Mencken
>
>
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--
Khalid M. Baheyeldin
2bits.com, Inc.
Fast Reliable Drupal
Drupal optimization, development, customization and consulting.
Simplicity is prerequisite for reliability. -- Edsger W.Dijkstra
Simplicity is the ultimate sophistication. -- Leonardo da Vinci
For every complex problem, there is an answer that is clear, simple, and
wrong." -- H.L. Mencken
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