6.9.2 Initial Parity sync extremely slow with new SMR drive

[Dash----]

Hey guys

 

quick question on what to expect with first parity sync. I have 2x4tb ironwolf drives from before in my hp gen8 microserver - both for data + 1TB cache ssd.

 

I now added 2x8tb smr (seagate barracudas). Over the night I transferred my media to the new 8tb drive (cca 2tb in 14h) and today I added a parity drive. Now, I do understand (or thought I do) problems of SMR drives, but creating of the parity is going extremely slow - it made 215GB in last 3 and a half hours. Transfer speeds started with 100MB/s+ and are now between 3-15. Am I doing something wrong? Going through the forums I understood that sequential writes should not have such a penalty.

I did extended smart test during the night before and both of them looked fine as well...

When I first encountered the issue, I cancelled the parity sync after an hour and changed bios setting to sata ahci and enabled cache in bios, but it does not seem to have done any difference .
 

Adding diagnostics here if someone catches anything.

Again, I understand the speed limitations of re-writing the data in daily use, but this seems excessive.

atlas-diagnostics-20210429-2012.zip

[JorgeB]

ST8000DM004 - These disks are known to sometimes perform very bad, apparently only some of them, older Seagate Archive SMR disks performed much better.