Hello community,
TrueNAS Scale Dragonfish 24.04.0 here, running under Proxmox (host CPU i9 14900K 128GB RAM total). TrueNAS VM = 16 Cores, 32GB RAM assigned.
On host I have a 10Gb Intel X710-T4 while on a client I have the Intel x550-T1 10Gb.
Pool are formed by 4x12TB Ironwolf Pro (vdev 2 mirrors).
When I trasfer big files, it starts with about 1 GB/sec:
But after a while the speed decrease to 400 MB/sec:
This is happening on all big files I trasferred from PC to NAS, while from NAS to PC I can get 500/600 MB/sec constantly.
Is it normal this behaviour? What could be the technical reason?
Thank you
Lucas
You’re likely hitting a limit on transaction group timeout (which is 5 seconds by default, as seen in /sys/module/zfs/parameters/zfs_txg_timeout). Once that drops you’ll be writing at the speed the pool can sustain.
As for why you can recv at a much higher rate from the NAS, sustained reads from pools are typically a lot faster than sustained writes, the data you’re accessing may also be in ARC.