| reply to aurgathor
Re: degradation of SSDs Turns out, according to the mfg it was a couple of FW bugs -- in short, their algorithm didn't take into account the possibility of power loss during operations. They tried to do GC and block erase at the same time w/o backing up the L2P table, for one. 
In most cases it was just a minor nuisance, but in one case that totally hosed a Win 8 install.
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Wacky Races 2012! |
| reply to aurgathor
After a bit (??) more testing, it's obvious that the degradation is happening.
One SSD started like this:
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE
1 Raw_Read_Error_Rate PO---- 100 100 070 - 0
5 Reallocated_Sector_Ct PO---- 100 100 000 - 0
9 Power_On_Hours -O---- 100 100 000 - 0
12 Power_Cycle_Count -O---- 100 100 000 - 518
177 Wear_Leveling_Count PO---- 100 100 000 - 2953
178 Used_Rsvd_Blk_Cnt_Chip PO---- 100 100 000 - 0
181 Program_Fail_Cnt_Total PO---- 100 100 000 - 0
182 Erase_Fail_Count_Total PO---- 100 100 000 - 0
187 Reported_Uncorrect -O---- 100 100 000 - 0
192 Power-Off_Retract_Count PO---- 100 100 000 - 28
196 Reallocated_Event_Count PO---- 100 100 000 - 0
198 Offline_Uncorrectable PO---- 100 100 000 - 0
199 UDMA_CRC_Error_Count PO---- 100 100 000 - 0
232 Available_Reservd_Space PO---- 100 100 010 - 0
241 Total_LBAs_Written PO---- 100 100 000 - 2433
242 Total_LBAs_Read PO---- 100 100 000 - 1437
||||||_ K auto-keep
|||||__ C event count
||||___ R error rate
|||____ S speed/performance
||_____ O updated online
|______ P prefailure warning
and ended like this:
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE
1 Raw_Read_Error_Rate PO---- 100 100 --- - 0
5 Reallocated_Sector_Ct PO---- 100 100 --- - 24576 (0 6)
9 Power_On_Hours -O---- 100 100 --- - 46
12 Power_Cycle_Count -O---- 100 100 --- - 7132
177 Wear_Leveling_Count PO---- 100 100 --- - 28168
178 Used_Rsvd_Blk_Cnt_Chip PO---- 100 100 --- - 4
181 Program_Fail_Cnt_Total PO---- 100 100 --- - 0
182 Erase_Fail_Count_Total PO---- 100 100 --- - 0
187 Reported_Uncorrect -O---- 100 100 --- - 51
192 Power-Off_Retract_Count PO---- 100 100 --- - 6640
196 Reallocated_Event_Count PO---- 100 100 --- - 51
198 Offline_Uncorrectable PO---- 100 100 --- - 30
199 UDMA_CRC_Error_Count PO---- 100 100 --- - 0
232 Available_Reservd_Space PO---- 096 096 --- - 0
241 Total_LBAs_Written PO---- 100 100 --- - 9071
242 Total_LBAs_Read PO---- 100 100 --- - 199484
||||||_ K auto-keep
|||||__ C event count
||||___ R error rate
|||____ S speed/performance
||_____ O updated online
|______ P prefailure warning
Note: some of the numbers such as Power_On_Hours are definitely incorrect. (there were over a month between the 2 snapshots) On the other hand, Power_Cycle_Count is correct. (I'm keeping an independent count of the cycles)
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Wacky Races 2012! |
