Slow speed when balancing with using NVME Cache to HDD.

[VirulentPip]

I have checked other posts which all seem to have no solution or clicking the prioritise arrows helps, but can seem to find a solution.

I can transfer to drivepool folder directly at like 210MB/s and I can use drivepool without cache and speed is also 210MB/s. Of course this speed varies depending on the drive that is being transferred to (space remaining wise). However when balancing from Cache speed doesn't seem to exceed 20MB/s.

I have no idea if this has always been an issue, but noticed recently when my backblaze uploads were still going or hadn't uploaded anything new (Set to start at 02:00 till finish, with balancing starting at 00:00)

Any suggestions for things to check?

Thanks in advance.
 

[Christopher (Drashna)]

Just a heads up, the balancing is done with a background I/O priority.  This means that if the disk(s) are being used for anything else, then it will cede priority to those other tasks.  

So if you do have something like backblaze running too, it may run slower.  Also, even if the disk that is being written to is fast and not busy, it is still limited to the read speed from the other drive(s).

 

 

[VirulentPip]

Thing is I wouldn't mind if it was a bit slow than the 210MB/s that I see when it writes directly to the Pool going to that HDD, even half speed would be 5x what it is reaching maxing out at 20MB/s is considerably slower and the only difference is the balancing process, just seems like a huge dip and confuses me. 

Edit - Backblaze is set to "Once Per Day" Two hours after the balancing starts, so shouldn't be causing any slow downs.. Albeit it cause balancing is so slow, it can overlap. 

[Christopher (Drashna)]

It might help to boost the priority:
https://wiki.covecube.com/StableBit_DrivePool_2.x_Advanced_Settings

Set the override value for "FileBalance_BackgroundIO" to false, and restart the service. 

And if that doesn't help, could you open a ticket at https://stablebit.com/Contact ? 

[YenForYang]

Curious if this is still an issue, or whether you found a solution. I'm wondering if it's an issue with the SSD, did you check the read speed and write speed on it?