Opinion on installation considerations (Drives, Cache,...)

[Cedus]

Hi everyone!

I'm planning on installing FreeNAS on a refurbished 19"-rackserver with at least 12 drive bays. Initally I would use 4 bays with 8TB SATA-disks (my old NAS-drives) and use a mirrored 32G usb-drive to boot FreeNas from. These are the only fixed points. Vendor of server, Controller, RAM-size, etc. are variables.
Since I need to use jails (ELK/DiskOver) for file search and indexing AND want to be able to bypass any future performance issues, my question is: does it make sense to add 2x server-SSDs (also mirrored) where I can put my jails and also ZIL? Can both data reside on it? What are your considerations about the size of ZIL and L2ARC and ultimately the RAM? And: if the system is working stable I want to be able to expand it with about 6 additional disks á 16TB for my files.
I think 32GB RAM (8GB + 4 drives above 8 à 1GB + jails-memory + L2ARC) should be a more than good start...

Thanks in advance for your answers!

 

[danb35]

use a mirrored 32G usb-drive to boot FreeNas from.

Why not a SSD? It doesn't need to be very big, but it will be much faster and (more to the point) more reliable than a USB stick.

and also ZIL?

What makes you think you need a ZIL (really a SLOG) device? The only place it would provide any performance improvement would be with sync writes, and nothing in your stated use case suggests that those would be in play.

L2ARC

I'd say more RAM would be in order before you'd think about L2ARC. You're suggesting 32 GB of RAM, which is probably good to start with, but I recall 64 GB as a minimum before you'd think about L2ARC.