September 22, 20223 yr Copying from usb3 external NVMe ssd to cache drive NVMe so why is it so slow? Is there a problem with speed if you use a cache pool mirror? I have 1x gen4 NVMe & 1x gen3 NVMe on the motherboard as a cache pool - so the gen4 is mirrored to the gen3. When I use diskspeed test docker both SSD drives are around 2300MB/s. It shouldn't be touching the array disks. The share is set to use Cache. But anyway I am copying direct to cache rather than the user share. The array drives test around 240MB/s down to 108MB/s. My understanding is USB 3 provides up to 500MB/s read & write. ( Dependent upon encoding overhead ) And USB 3.1 up to 1200 MB/s read & write. ( Dependent upon encoding overhead ) Edited September 22, 20223 yr by dopeytree
September 23, 20223 yr Solution 14 hours ago, dopeytree said: My understanding is USB 3 provides up to 500MB/s read & write. ( Dependent upon encoding overhead ) First ver. actual throughput will be 300MB/s and I am not sure Unraid support newer version or not even you have 3.2 gen 2 controller & device.
September 23, 20223 yr Author Most online benchmarks put usb3 real throughput at around 400MB/s. Have noticed USBc port doesn't work out the box with unraid. USB3.2 gen1 works tho. Anyway even internally avoiding USB & Sata seem to get slow copy's even just NVMe to NVMe.. any ideas I should explore?
September 28, 20223 yr Author Update - fixed this slow copy issue by installing the Auto Turbo Write Plugin!!! Everything is now insanely fast.
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