[Bglug] Error detecting file system on single drive

[Bob Jonkman]

You could always divide your NVME drive into two partitions, then mirror 
them with mdadm. It won't protect you from catastrophic drive failure, 
but it'll catch and correct the bit flips. Doubles the cost of your 
storage, tho.

I guess you could divide it into three partitions and use RAID5, costing 
you only 1/3 of the capacity...

--Bob.

On 2021-12-17 18:35, Andrew Howlett wrote:
 > Yes, exactly as Dan suggests. I have all my documents, projects, photos,
 > music, etc in my home partition. Approaching 8x10E12 bits of data. Which
 > makes me think bit flips might be statistically probable. Backups will
 > just make a copy of the flipped bits. Error detection on the home
 > partition would warn me before I make a bad backup, give me an
 > opportunity to restore from a good version.
 >
 > On Dec. 17, 2021 2:29 p.m., bglug at eriksen.ca wrote:
 >
 >
 >     I believe that Andrew was asking about filesystems like btrfs or zfs
 >     which use checksums to verify data whenever blocks are read. They
 >     will throw errors if the checksums fail. These filesystems are often
 >     set to check all data once a month and with the size of hard drives
 >     these days, bitrot is real and you are likely to have data integrity
 >     fail at some point. Older filesystems do not detect when the data
 >     has changed through errors like failures or bit-flipping from solar
 >     flares.
 >
 >     These filesystems are best when used on multiple drives because they
 >     will automatically correct data errors on one drive using the second
 >     (raid1 and the like). But he wondered if there is any point on a
 >     single drive where the filesystem can detect the error but cannot
 >     actually fix the error.
 >
 >     I am heavy into zfs use for my data and make extensive use of it
 >     features. I use btrfs on the boot drive for boot compatibility.
 >
 >
 >     Dan
 >
 >     On December 17, 2021 2:17:19 p.m. EST, "Andrii (Logan) Zvorygin"
 >     <andrii at liberit.ca> wrote:
> I re-read what you said, and it seems you are asking whether to
>>     have SMART functionality for your NVMe drive. To this I also have to
>>     say yes.
> 
> Though my understanding is that it comes as a standard part of all
>>     nvme drives, so I don't think you need to pay any extra for it.
> 
> It's apt-get install nvme-cli on ubuntu
> 
> example of usage:
> 
> sudo nvme smart-log /dev/nvme0
> Smart Log for NVME device:nvme0 namespace-id:ffffffff
> critical_warning                    : 0
> temperature                         : 52 C
> available_spare                     : 100%
> available_spare_threshold           : 5%
> percentage_used                     : 36%
> data_units_read                     : 299,418,327
> data_units_written                  : 180,406,142
> host_read_commands                  : 4,307,854,444
> host_write_commands                 : 3,778,155,597
> controller_busy_time                : 29,063
> power_cycles                        : 110
> power_on_hours                      : 28,346
> unsafe_shutdowns                    : 90
> media_errors                        : 0
> num_err_log_entries                 : 0
> Warning Temperature Time            : 0
> Critical Composite Temperature Time : 0
> Temperature Sensor 1                : 52 C
> Thermal Management T1 Trans Count   : 0
> Thermal Management T2 Trans Count   : 0
> Thermal Management T1 Total Time    : 0
> Thermal Management T2 Total Time    : 0
> 
 >      >
 >      >
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 >      >Group at bglug.ca
 >      >http://bglug.ca/mailman/listinfo/group_bglug.ca
 >
 >     --
 >     Sent from my phone. Please excuse my brevity.
 >
 >
 >
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-- 
Bob Jonkman <bjonkman at sobac.com>          Phone: +1-519-635-9413
SOBAC Microcomputer Services             http://sobac.com/sobac/
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