Getting only 9MB/s to my SSD cache. Just by copying a big file through windows networking to a share that uses an SSD as cache. Such SSDs are fast enough to saturate the 1Gb ethernet connection from the client, and the unraid server is connected on 10Gb. There are no other processes accessing the array. Even without cache, directly to the HDDs then, it should still easily be able to saturate a 1Gb network. The other way, server to client, is even worse at around 6MB/s. I also don't see anything that is blocking up the CPU, memory utilisation, or any other significant I/O.

 

It's also not intermittent. The slow speed is constant. It will not improve if I leave the file copy going. It also doesn't improve if I let things settle by giving it a few minutes and then trying again.

 

Another thing worthy of note is that in the "main" tab, I see 0.0B/s for every disk/ssd involved all the time (in both directions). It's like it's copying to/from the memory cache, which would be great, but should be able to saturate ten network connections with bandwidth to spare. So that doesn't explain why it's so slow. Rather I think something is broken.

 

I would expect at least 100MB/s in each direction. And preferably also see that reflected on the "main" tab. So what's blocking it up?

unraid-diagnostics-20231228-1504.zip

Edited December 28, 20232 yr by thany

If you get the same speed writing to the array start by running a single streem iperf test in both directions to confirm the LAN is OK.