ST2000LM007 - Weird Read Issue

[Joep]

affirmative, over

[lcoughey]

Got another one

Patient Drive - ST1000LM035, 1RK172-036, WL1..., SBK3, 2 heads

Head 1 is the offender

Seagate-moLD.png (47.23 KiB) Viewed 12171 times

[pclab]

I'm also having the same issue with this drive. One head reads fine (files are ok), but head 1 just trow trash out even with all sectors green...
A head swap will be done and I will post the feedback here!

[Abdurrahim.sopon]

this is new and very common issue of LM hdd.

[fzabkar]

Just to be clear, do these bogus sectors occur in groups of 8?

[fzabkar]

Here is another Seagate SMR model (ST4000DM004) where the user has experienced insidious data corruption:

https://forum.hddguru.com/viewtopic.php?f=1&t=40740

In this case SMART reported no errors, and no read errors were seen by the OS, but GP Log 0x04 contained 20 Reported Uncorrectable Errors. The only reason that the user was aware of any corruption was because his file system (BTRFS) automatically computes checksums for each file. This is clearly a firmware bug (Seagate weren't too interested in my bug report).

[lcoughey]

Basically, what is happening is that if the drive timeout is long enough, it sends back one of the two patterns for bad sectors, rather than reporting them as bad. I have found that if you drop the timeout down to 100ms, it will get reported as unreadable.

[DRG]

Hi Luke!,

It's my understanding that once a sector shows those patterns you mention, the original data in those affected sectors is overwritten with gargabge permanantly. Have you found this to be the case?

[lcoughey]

No, the data in the original sector is theoretically there and can frequently be recovered with multiple reads or donor heads. The pattern we see is only given if the timeout is long fairly long...if you set it to 100ms, it will likely report an error, rather than provide garbage.

In PC3000, you can manually setup a map that will populate based on sector contents. MRT just added it to their default map, so no configuration is needed.