10G FreeNAS to DL380 Gen8


i have a TrueNAS server running 5x WD RED drives with just under 2TB of used space, I want to offload the data from the trueNAS server to one of my DL380e Gen8 servers.

DL380 - 3.5" X4 SAS drives on a P420i controller setup in RAID 5 also a SSD as the OS drive seprate array. i want to install a 10G nic using DAC cable to a 10G Nic to the trueNAS so its quicker to offload

the spec of the TrueNAS
CPU - i3-8100 4 cores

my question is will i get anything close to 500 + mb/s transfer speeds to make it worthwhile ? as read that the bottleneck on some 10g systems can be the CPU, Memory etc…

would be happy with 300 + mb/s tbh

whats everyones thoughts ?

looking at getting the Chelsio 320 for the FreeNAS and a Intel x520 for the DL380 and a Unifi 16port Unifi Fibre Switch


You might be looking somewhere between the 300-500mbps range. Those Reds probably top out at 125mbps each, so it’ll depend on your pool configuration.

There’s been a few improvements over recent years that have made 10g easier to saturate with commodity hardware. Your i3 is twice as fast single threaded as my e5-2620s which can saturate 2x 10g links.

Basically, your disks will be your bottlenecks here not networking. Even your single SATA SSD would bottleneck a 10g transfer.


Thanks for the reply,

If i were to add 2x Cache SSDs 1TB each to the FreeNAS box, would that improve the transfer speeds ?


I believe current guidance for SLOG (write cache) is a small Optane drive, STH has some recommendations here for SLOG drives. You don’t need them to be large, 256GB is plenty.

As for read, you’d want to up your RAM and possibly add something like a 480GB NVMe drive, doesn’t have to be as high end as the write cache. This would be your L2ARC (Level 2 Adaptive Replacement Cache), which is secondary to your memory. STH has recommendations for those also, here.