Hi to everyone! 
There is a question about a hard drive and a parity check speed.
May be these issues are independent, I cannot say.
The array is 4x14TB WD White from WD Elements.
3x WD140EMFZ-11A0WA0
1x WD140EDFZ-11A0VA0
They have been working a little over 2 years without problems. I noticed that for the last 2 monthly Parity checks it took 4 hours longer, since the average speed fell from 158 MB/s to 136 MB/s.
  
Action          Date                                        Size   Duration                           Speed        Status Errors
Parity-Check 2023-03-06, 16:34:51 (Monday) 14 TB 1 Day, 4 HR, 3 Min, 57 Sec  138.6 MB/S OK       0
Parity-Check 2023-02-03, 02:47:57 (Friday)  14 Tb 1 Day, 4 HR, 30 Min, 12 Sec 136.4 MB/S OK       0
Parity-Check 2023-01-07, 07:53:01 (Saturday)14 Tb 1 Day, 30 Min, 26 Sec        158.7 Mb/S  OK       0
Parity-Check 2022-12-05, 09:06:33 (Monday) 14 Tb 1 Day, 25 Min, 40 Sec         159.2 Mb/S OK       0

 

I checked the logs of the discs, the WD140edFz showed the following entry twice in the log "kernel: ata7.00: supports DRM functions and may not be fully accessible".
WD140emfz does not have such lines in the log.
HW is all the same, I did not change anything in the config either. Bios has been updated in early December, before the last quick parity check.
I tried to google it, but did not find an understandable answer.
Could you advise me, what may this mean and how to deal with it?

Could it be the SATA cable issue leading to both slower speed and errors in the log?

Edited March 10, 20233 yr by koaly

1 hour ago, koaly said:

kernel: ata7.00: supports DRM functions and may not be fully accessible

This should not be an issue, post diags after the next parity check, or current ones if you didn't reboot yet, you can also run a test with the diskspeed docker to see if all disks are performing normally.

1 hour ago, JorgeB said:

This should not be an issue, post diags after the next parity check, or current ones if you didn't reboot yet, you can also run a test with the diskspeed docker to see if all disks are performing normally.

Thanks for the reply. I was just wondering what these lines in the log may mean?

I switch off the server daily as there are no overnight tasks and also in order to save some electricity, which became 3 times more expensive in Europe.

As for the benchmark, it did not show any significant difference between 4 drives. 

I will do the parity check next time and post an update with the diags if it does not improve.

Spoiler

Edited March 10, 20233 yr by koaly

Quote

This message means nothing, the DRM means drive support IEEE 1667 Storage SILO encryption.

Whatever that is

https://forums.gentoo.org/viewtopic-t-1040712-start-0.html