Ubuntu Server & L2ARC on Same Drives

[norsemangrey]

I'm looking for some advice on partitioning a new system with multiple disks for root on ZFS with Ubuntu Server 20.04. This is the hardware I have:

• 2 x Intel D3-S4610 256 GB SSD
• 4 x Seagate EXOS 7E8 8TB
• 32 GB ECC RAM (planning of expanding to 64 GB later)

In brief, this is what I tentatively think I want to do:

• The two SSDs in a mirrored vdev for Ubuntu install.
• Use most of the space on the SSDs for persistent L2ARC (in a striped configuration).
• The four HDDs in a mirrored striped vdev configuration for storage.

I have read and plan on following the Ubuntu 20.04 Root on ZFS guide, but I have read up a lot on the topic lately I have limited experience with ZFS and Linux and do not understand all the aspects. I assume that following the install guide, I will get what I need in terms of partitions for rpool, bpool, EFI and swap. I see there are some warnings about the swap though, but I do not know whether or not I actually need it. How do I determine this and what is the alternative if not using it.

With regards to the L2ARC what would I need to do to configure this (what would be the actual commands)? Is that something I would do after completing the Ubuntu install guide? Do I need to change or modify any parts of the instructions in the guide to allow for the additional partition for the L2ARC?

 

[andrewbedia]

What use case are you trying to target here? Storing your movies? Multiple people accessing documents/roaming profiles? Virtual machine storage? A lot of usages have no benefit to L2ARC and will just wear your SSDs out.

Is this for a hobby/home use or is this for something important/production use?