I keep seeing conflicting things about usable space in my case, and I could not find an online calculator that allows for different-size disks. My NAS will have 2 x 2TB SSD 2 x 6TB HDD What do you think is the best configuration to use this space, with as little wasted space and with some protect…

Wow, that’s a lot of useful information. I’m a noob on NAS and ZFS, I appreciate all the assistance. Looks like 2 vdevs with paired storage is the way to go. Follow-up questions on caching. I have a NVME 500gb drive, and 16gb ram. I installed Truenas on a partition of 128gb on the NVME, and planni…

TrueNAS CORE uses (almost) all available RAM as ARC. So does the current release of TrueNAS SCALE. You don’t have nearly enough RAM to make use of L2ARC.

[image] oacikgoz: How do I configure the system to use 12gb physical ram for ARC? Asking because I’ve read that Truenas uses 50% physical ram by default. Current version of both Scale and Core use almost all free memory for ARC. This can be adjusted, but why?

I see, I didn’t know that… Thanks for clarification. L2ARC is not useful in my use case? Did I just buy 500g boot drive for nothing? :slight_smile:

[image] oacikgoz: Did I just buy 500g boot drive for nothing? Eh, pretty much. But was it a significant cost delta compared to something smaller? TrueNAS is designed to have a dedicated boot device. Yes, it’s possible to work around that design. But I really don’t recommend it.

Why wouldn’t L2ARC improve any performance for my system?

Ah, now I remember… special vdev vs L2ARC… is that of any use for my build?

ARC is very good. L2ARC needs space in the ARC for record keeping, thus reducing ARC effectiveness. You should run your system for a while, then see what your ARC hitrate looks like. It might be 99.5% which means only 0.5% would be eligible for speeding up by L2ARC. If the memory used by the L2AR…

Yes. You need at least two devices to make a special vdev (assuming you want to have a pool which is not one failure away from total loss)

Educate me on ZFS and capacity

TrueNAS General

dan May 22, 2024, 11:13pm 17

Yeah, I know. But in this case it’s a tendency that should be resisted. See:

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Educate me on ZFS and capacity

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