How to interpret the TrueNAS Scale disk performance Report?

devemia

Dabbler
Joined
Mar 5, 2023
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I have a flash pool in RaidZ2 with deduplication enabled. The network bandwidth is 10 gigabits, and the client machine's transfer rate hovers around 900-1100MB/s. All is good from a client's perspective.

When writing to the SMB drive, as I understand, the Memory report in TrueNAS indicates data are written to memory. It resides in memory for a while before being written to the flash. However, when looking at Disk I/O, the maximum transfer rate only hovers around 4 MB/s, this applies to all drives in the pool (about 20 MB/s in total). I initially thought that the data was being distributed across physical drives, so the sum of Disk I/O would be equal to 900-1100MB/s, but that was not the case here.

With that said, can someone explain the relationship between these data points to me? I'm still learning ZFS behavior so this is very helpful. Thank you.

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