Performance dropped with more drives

[IllSkillz]

I created a raidz1 with 3 drives and start my migration in to a new pool. The speeds was around 100 MB/s. After some time I decided to add two more drives in to the pool so I stopped my migration, deleted the pool and created a new raidz1 with 5 drives. But now write speed only 50MB/s. Is this expected performance drop or one of the drives if faulty?

 

[asap2go]

What drives do you use?
Check if they use a technology called SMR.
That's a common cause for performance problems.

 

[IllSkillz]

they are cmr drives

 

[asap2go]

they are cmr drives

Can you give your hardware specifications?
Do you use an HBA or raid card?
Which Version of TrueNAS?
Did you already run smart tests and scrubs?

 

[somethingweird]

I created a raidz1 with 3 drives and start my migration in to a new pool

Just curious what was the old pool?

 

[IllSkillz]

Can you give your hardware specifications?
Do you use an HBA or raid card?
Which Version of TrueNAS?
Did you already run smart tests and scrubs?

OS Version:TrueNAS-SCALE-23.10.0.1
Product:B760M DS3H AX DDR4
Model:12th Gen Intel(R) Core(TM) i5-12400F
Memory:31 GiB
Some of the drives are sitting on LSI 9205-8i IT mode
Scrubs is performed every month on an old pool.
Long smart have been done on a new pool, everything is fine.

 

[IllSkillz]

Just curious what was the old pool?

WD DC HC550 x3, speed dropped when i made WD DC HC550 x5

 

[Patrick M. Hausen]

With your first pool every write needed to go to three drives. Now every write needs to go to five drives. Of course that is slower.

 

[IllSkillz]

I imagine writes will go to all drives simultaneously, so speed of the pool will be the speed of the slowest drive.