Slow and weird pauses over 1 Gbps (video)

[rangopango]

I set up a test volume with a flash drive that's 27.3GB USB 2.0 and I'm getting weird pauses with Robocopy (local drive to the share).

robocopy "E:\files" "Z:\files" /MIR /ZB /COPY: DT /DCOPY: DT /R:15 /W:15 /TEE /V
I mapped a network to the drive letter Z, which would be the share.

https://my.mixtape.moe/skywkg.webm
What's causing it to pause like this? I've tried different switches, different cables, different drives and it's still happening.

edit: I tried Teracopy, but I ran a checksum instead. Less weirder pauses... but still weird pauses. Anyone got an idea why? Copying files with Teracopy causes the exact same pauses too.
https://puu.sh/zUWSj/89d3170c40.png

 

[kdragon75]

with a flash drive that's 27.3GB USB 2.0 and I'm getting weird pauses

Nothing weird about it. It's a flash drive with ZFS coping over CIFS. Its writing to cache and pausing until the cache can write to disk.

Don't use USB drives with ZFS. Even for testing. End of story.

 

[rangopango]

I'm testing it with one regular 8TB NAS drive with no errors and I'm getting speeds between 20 MB/s, 40 MB/s and the highest was 70 MB/s, but it fluctuates between 20-30 occasionally. Is this normal? The switch is rated for 1000 MB/s

With large files, I'm seeing a consistent 70 MB/s but with small (5-15 MB~) files, it fluctuates from 5 MB/s to 30 MB/s

 

[MrToddsFriends]

The switch is rated for 1000 MB/s

You switch is rated for 1000 Mbit/s while the other transfer rates mentioned by you are most possible expressed in MBytes/s.

It's normal that one gets far lower transfer rates with many small files than with large files due to overheads in SAMBA, in the files system and in the hardware (HDD head movement).

Benchmarking ZFS is not easy, if you are trying to go that route. Look out for sticky threads about this topic.