04-04-2018 08:11 PM
I have a Crucial CT525MX300SSD1 drive that I got in November. A third party smart utility started giving me a warning that "Reallocated NAND Block Count" indicates a failure when it went from zero to one in January. It has now gone to 4.
I downloaded Crucial Storage Executive and confirmed the "Reallocated NAND Block Count" value is 4.
But the is this a problem? I can understand a spinning magnetic surface developing defects, but why would a SSD need to reallocate blocks?
ID Description Attribute Data Units
--- -------------------------------- -------------- ----------
1 Raw Read Error Rate 4 Errors/Page
5 Reallocated NAND Block Count 4 NAND Blocks
9 Power On Hours Count 1210 Hours
12 Power Cycle Count 281 Power Cycles
171 Program Fail Count 0 NAND Page Program Failures
172 Erase Fail Count 0 NAND Block Erase Failures
173 Block Wear-Leveling Count 10 Erases
174 Unexpected Power Loss Count 58 Unexpected Power Loss events
180 Unused Reserved Block Count 1938 Blocks
183 SATA Interface Downshift 0 Downshifts
184 Error Correction Count 0 Correction Events
187 Reported Uncorrectable Errors 0 ECC Correction Failures
194 Enclosure Temperature 25 Current Temperature (C)
39 Highest Lifetime Temperature (C)
196 Reallocation Event Count 4 Events
197 Current Pending ECC Count 0 ECC Counts
198 SMART Off-line Scan Uncorrectable Errors 0 Errors
199 Ultra-DMA CRC Error Count 0 Errors
202 Percentage Lifetime Remaining 100 % Lifetime Remaining
206 Write Error Rate 0 Program Fails/MB
210 RAIN Successful Recovery Page Count 16 TUs successfully recovered by RAIN
246 Cumulative Host Sectors Written 4485081609 512 Byte Sectors
247 Host Program Page Count 140654766 NAND Page
248 FTL Program Page Count 110535820 NAND Page
04-04-2018 10:44 PM
It is normal for an SSD to sometimes report bad blocks during normal use as long as you don't get a lot of them in a short period of time and you still have reserve blocks available. Getting a bad block on an SSD is not quite the same impending doom as it usually is with a traditional hard drive. See this SSD endurance test for some interesting information about SSD failures.
Check to make sure you are running the latest firmware on the SSD which is currently at M0CR060. I strongly suggest updating to this version as I've had issues with earlier firmware causing the SSD to get stuck reallocating the bad blocks which then required a Secure Erase to get it working correctly again. Looking at your SMART Attributes I don't see this happening to you yet.
I've personally encountered similar but worse problems with multiple MX300s and got them all working again so far without any further issues.
Note: The SSD needs to be conected to an internal controller configured in AHCI mode in order to update the firmware.
Make sure to backup any data you want before doing anything just in case. So far I have not lost any data due to a firmware update, but there is always a risk.