Ubuntu 13.04. The number of bad sectors on my SSD has steadily increased until 226 bad sectors today.
The thing is, I don't know whether 226 bad sectors is 0.0001% of the SSD, 1% of the SSD, or 99% of the SSD.
I haven't found anything on the internet this morning to answer this question.
The Disks utility doesn't tell me either, and I can't find the information in SMART Data.
sudo smartctl -a /dev/sda shows this:
smartctl 5.43 2012-06-30 r3573 [x86_64-linux-3.8.0-31-generic] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net
=== START OF INFORMATION SECTION ===
Device Model: Samsung SSD 840 PRO Series
Serial Number: S1ATNEAD645474H
LU WWN Device Id: 5 002538 5503c15c0
Firmware Version: DXM05B0Q
User Capacity: 256,060,514,304 bytes [256 GB]
Sector Size: 512 bytes logical/physical
Device is: Not in smartctl database [for details use: -P showall]
ATA Version is: 8
ATA Standard is: ATA-8-ACS revision 4c
Local Time is: Fri Jan 24 20:37:08 2014 CST
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: (53956) seconds.
Offline data collection
capabilities: (0x53) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
No Offline surface scan supported.
Self-test supported.
No 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: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 20) minutes.
SCT capabilities: (0x003d) SCT Status supported.
SCT Error Recovery Control supported.
SCT Feature Control supported.
SCT Data Table supported.
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
5 Reallocated_Sector_Ct 0x0033 097 097 010 Pre-fail Always - 238
9 Power_On_Hours 0x0032 099 099 000 Old_age Always - 1331
12 Power_Cycle_Count 0x0032 099 099 000 Old_age Always - 341
177 Wear_Leveling_Count 0x0013 097 097 000 Pre-fail Always - 75
179 Used_Rsvd_Blk_Cnt_Tot 0x0013 097 097 010 Pre-fail Always - 238
181 Program_Fail_Cnt_Total 0x0032 097 097 010 Old_age Always - 238
182 Erase_Fail_Count_Total 0x0032 100 100 010 Old_age Always - 0
183 Runtime_Bad_Block 0x0013 097 097 010 Pre-fail Always - 238
187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0
190 Airflow_Temperature_Cel 0x0032 067 062 000 Old_age Always - 33
195 Hardware_ECC_Recovered 0x001a 200 200 000 Old_age Always - 0
199 UDMA_CRC_Error_Count 0x003e 099 099 000 Old_age Always - 1
235 Unknown_Attribute 0x0012 099 099 000 Old_age Always - 128
241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always - 33308592070
SMART Error Log Version: 1
No Errors Logged
SMART Self-test log structure revision number 1
No self-tests have been logged. [To run self-tests, use: smartctl -t]
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
255 0 65535 Read_scanning was never started
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.
The smart data of our SSD says that you used the SSD for 1331 hours and your SSD has suffered 33308592070*512/1024^4=15,5 TiB writes. That means ca. 12 GiB writes per power on hours on your SSD. That is kinda lot for a typical consumer SSD usage. What do you use the SSD for?
You are still way below the write cycle limit of your SSD, which is an MLC based one, so should tolerate ca. 3000 write cycles, which would mean ca. 256GB*3000=768 TB writes. So I would say you are safe.
But your SMART data shows that now you have already 238 reallocated (failed) sectors. That number is still very low compared to the few hundred million sectors on your drive, but for me it is surprising that after only 60-70 write cycles your SSD has failing blocks. Do you have some spare space on your SSD? The SSDs needs some spare space to be able to efficiently manage the wear on the drive. If the drive is almost full it wears faster because of the increased writes of the wear leveling algorithm.
Here is a graph showing a 840 PRO 256 GB SSD under write test. It has still zero, or very close to zero reallocated sectors after 300 TB writes. You have more than 200 after less than 20 TB.
You are using the latest firmware of the drive. I don't want to worry you but I think you should contact Samsung with that SMART output, and ask about their opinion. I think your drive has some kind of problem.
UPDATE:
After Samsung's response - who basically said everything is fine - I would say that as long as you don't encounter data loss, (that is as long as the badblocks discovered during a write operation) I think you shouldn't worry then.
You can see the badblock count in the Runtime_bad_block line (238, the Raw value) that is the sum of the Program_Fail_Cnt_Total (238, which is the failed write operations) the Erase_Fail_Count_Total (0, which is the failed erase operations) and the failed read operations. So the failed read operations on your drive at the time the smart output was generated is 238-238-0=0, so you didn't have any failed read, you don't have any data loss.
If your drive starts to encounter failed reads too in the near future (that means the Runtime_bad_block will not equal Program_Fail_Cnt_Total + Erase_Fail_Count_Total), potential data loss, I would recontact Samsung. Until that time just enjoy your SSD.
It eventuated that that Samsung 840 Pro SSD had a catastrophic failure later in 2014. It was replaced under warranty with the Samsung 850 Pro, which has now been running successfully since then, and still does not report any bad sectors. I'm pleased about that, because I thought maybe it was an "undocumented feature" of SSDs.