Initial Setup

OK, now for some technical details. We will test the SSD on a standard Linux server running CentOS 6u6, though pretty much any reasonably modern platform and distro would do.  The initial server (we plan to change it in due course) will only support SATA2, so read and write performance will be capped to a theoretical maximum of 300MB/s and it will be interesting to see how close we can get to this figure.

Now for the SSD itself.  The one we will use is nearly, but not quite, brand new - we have run some performance tests on it to establish baselines, which should have no impact on the validity of this test.  So its initial SMART values are:

ID# ATTRIBUTE_NAME          VALUE WORST THRESH TYPE      RAW_VALUE
  5 Reallocated_Sector_Ct   100   100   010    Pre-fail  0
  9 Power_On_Hours          099   099   000    Old_age   436
 12 Power_Cycle_Count       099   099   000    Old_age   158
177 Wear_Leveling_Count     099   099   000    Pre-fail  7
179 Used_Rsvd_Blk_Cnt_Tot   100   100   010    Pre-fail  0
181 Program_Fail_Cnt_Total  100   100   010    Old_age   0
182 Erase_Fail_Count_Total  100   100   010    Old_age   0
183 Runtime_Bad_Block       100   100   010    Pre-fail  0
187 Reported_Uncorrect      100   100   000    Old_age   0
190 Airflow_Temperature_Cel 065   060   000    Old_age   35
195 Hardware_ECC_Recovered  200   200   000    Old_age   0
199 UDMA_CRC_Error_Count    100   100   000    Old_age   0
235 Unknown_Attribute       099   099   000    Old_age   26
241 Total_LBAs_Written      099   099   000    Old_age   16682136274

Note: the '235 Unknown Attribute' is 'Power Recovery Count' - full details on SMART attributes for Samsung SSDs can be found here.

The key health indicators for longevity are ‘Wear Leveling Count’ and ‘Total LBAs Written’, which will indicate how the drive is faring as it ages.  Eventually, the reallocated sector and error counters will become significant, but hopefully not just yet!

So - looking at the last line, total data written is 16682136274 (total LBAs written) * 512 (LBA or sector size) = 8.5TB, and the SSD calculates that it still has 99% life left.  This is great, and suggests that we may be able to get much more life than Samsung’s rated 150TBW.  And a wear levelling count of 7 also equates to 99%, so all in all this is a good place to start from.

Coming soon:

Initial Results