USB 3.0 poor performance

[zchrish]

Hi,

I am trying to use either FreeNAS 11.x or TrueNAS 12.x and when trying to use either a USB flash stick or a USB NVME, the performance is poor. I am getting around 40MB/sec instead of either 100-200MB/sec with my HDD or ~600MB/sec with SDD. Even dd shows poor performance of around the same. I have seen threads in 2020 and earlier that describe the issue; I am simply posting an additional data point and suggest the issue be investigated and fixed. I downloaded Ubuntu 20.04 and set-up equivalent zfs drives on hdd and USB and this platform doesn't exhibit the issue.

BTW, is it possible to switch the underlying OS from FreeBSD to Linux? Or at least make it agnostic so that the end user can select it themselves? I am aware of the zfs legality.

Thanks,
Chris

 

[Ericloewe]

s it possible to switch the underlying OS from FreeBSD to Linux

No, but a version based on Linux, TrueNAS Scale, is under development and you can give it a spin. Usual warnings about pre-release software apply.

I am aware of the zfs legality.

You mean license incompatibility? IANAL, but the consensus outside the Linux kernel FUD, NIH echo chamber is that there is no real problem. See, e.g. that Canonical has been doing it for many years now with not as much as an angry letter from Oracle. And Oracle is not shy about using their legal department.

 

[sretalla]

trying to use either a USB flash stick or a USB NVME

For ZFS data pool storage, this is not a recommended arrangement in any case.

TrueNAS SCALE may provide different results (due to having a different set of USB drivers to FreeBSD), but that doesn't change the problems with ZFS and USB controllers. (ZFS will tend to quickly wear out many types of USB controllers due to the way it submits transaction groups in big batches of IO).

We see that it's sustainable for the boot pool, which typically doesn't do a lot of bulk reading/writing... although it does show up poor quality USB sticks if used for boot pool, but for data pools, ZFS will wear out your USB controller in all likelihood, it's just a matter of time.