Memory usage

[Kane_S]

I’m currently running 25.10.0.1 - Goldeye, I have 124.9 GiB DDR5 ECC memory. It’s currently showing the following:

Free: 7.0 GiB

ZFS Cache: 101.7 GiB

Services: 16.3 GiB

I have 8 different Applications running, and 5 VM’s (3 different Ubuntu Servers), 4 different shares via SMB.

CPU is running very low, 5 - 7% most times, most network traffic is through a 10G connection, with admin through a 1G connection.

Everything is running smoothly without issues, just more curious why the ZFS Cache is sucking up most available memory? Before moving over to 25.10.0.1, I had more free memory. I’ve had TrueNAS running on the machine for one year now. I built it in November last year.

Here’s what my NAS is: a bit overkill, but for home, I kinda like to tinker and mess about.

The board is ASRockRack B650D4U-2L2T/BCM, with 128 GiB ECC DDR5 memoryCPU: AMD Ryzen 7 7700X 8-Core Processor (I’m thinking of changing to one of the Epyc CPUs later on)

I have this all stuffed into a Sliger CX3702 NAS case, 5, 3.5 drives, 7, 2.5 SSDs, and one NVMe drive

[LarsR]

For zfs free ram is wasted ram. If another process or service needs ram it will shrink down the arc automatically

Edit:
And in the past, there was a 50% limit on arc ( an older zfs on Linux limitation) which got removed and now arc is close to the way it was with Truenas core

[Kane_S]

Thank you LarsR, I’ve only been doing this for the past year. I’ve very happy with TrueNAS, but like everything, there’s a learning curve involved

Your explanation makes sense, again thanks for the response!

[Kane_S]

Here’s a brief look at what I have, it’s fairly basic for a home server