Thunderbay6 write speeds slow

As you surmise, write speeeds should be much faster, closer to reads.

I am not sure what is causing this.

First thing to try is that your disks are OK.
I am assuming there is no data on the volumes yet.

Try a zero disk, on each disk in turn. Open Activity Monitor and on the disk tab, ensure you are getting ~150MB/s or more on each drive. then you can remove the disks as the cause.

You are running 5.7.2? is the SoftRAID Monitor always running in the menu bar?

Next, do you have a backup OS to test with? I would try that next.

As far as the support file, we do not have a System Profiler report, but the file does contain basic information about your system, disk formats and the System log and SoftRAID log. We also capture up to 3 crash logs. The reason it is not "user readable" is it contains information that allows us to recreate your SoftRAID GUI experience in our support machines. that makes supporing users very easy, as there is a lot of diagnostic information in the disks and volume tiles if you know how to view them.

After going through all kinds of tests, it seems as though everything is actually fine and the Blackmagic disk speed app misled me. For whatever reason, that app is running very slow write speeds. The AJA speed test utility and other tests I ran (straight Finder copies, cp copies, etc) returned more sensible numbers.

SoftRAID zero disk - activity monitor reported 208 MB/s per disk (varying 176-304 MB/s but 208 was most common number)

AJA results (write/read):
708/877 MB/s
713/934 MB/s

ioping test results per disk:

--- /dev/rdisk21 (block device 7.28 TiB) ioping statistics ---
24 requests completed in 288.5 ms, 96 KiB read, 83 iops, 332.7 KiB/s
generated 25 requests in 24.0 s, 100 KiB, 1 iops, 4.16 KiB/s
min/avg/max/mdev = 4.16 ms / 12.0 ms / 18.8 ms / 3.77 ms

--- /dev/rdisk22 (block device 7.28 TiB) ioping statistics ---
24 requests completed in 303.1 ms, 96 KiB read, 79 iops, 316.7 KiB/s
generated 25 requests in 24.0 s, 100 KiB, 1 iops, 4.16 KiB/s
min/avg/max/mdev = 5.26 ms / 12.6 ms / 17.7 ms / 3.18 ms

--- /dev/rdisk23 (block device 7.28 TiB) ioping statistics ---
24 requests completed in 291.6 ms, 96 KiB read, 82 iops, 329.3 KiB/s
generated 25 requests in 24.0 s, 100 KiB, 1 iops, 4.17 KiB/s
min/avg/max/mdev = 5.50 ms / 12.1 ms / 20.8 ms / 3.66 ms

--- /dev/rdisk24 (block device 7.28 TiB) ioping statistics ---
24 requests completed in 314.9 ms, 96 KiB read, 76 iops, 304.9 KiB/s
generated 25 requests in 24.0 s, 100 KiB, 1 iops, 4.16 KiB/s
min/avg/max/mdev = 3.43 ms / 13.1 ms / 19.6 ms / 3.45 ms

--- /dev/rdisk25 (block device 7.28 TiB) ioping statistics ---
24 requests completed in 319.9 ms, 96 KiB read, 75 iops, 300.1 KiB/s
generated 25 requests in 24.0 s, 100 KiB, 1 iops, 4.16 KiB/s
min/avg/max/mdev = 8.29 ms / 13.3 ms / 19.6 ms / 3.40 ms

--- /dev/rdisk26 (block device 7.28 TiB) ioping statistics ---
24 requests completed in 254.8 ms, 96 KiB read, 94 iops, 376.8 KiB/s
generated 25 requests in 24.0 s, 100 KiB, 1 iops, 4.17 KiB/s
min/avg/max/mdev = 5.59 ms / 10.6 ms / 16.2 ms / 3.22 ms

Great! I will keep that in mind when getting benchmark complaints from users!