I've been upgrading one of our old pools at work, going from 512B drives to 4K. However, I realized that I wanted to keep our SSD L2ARC, which reports 512B sectors (which I think it actually is). I also stumbled across an old thread that suggests that even if your L2ARC device is 512B, it should be overridden and forced to 4K. My questions are:
- Is this (forcing 4K on a cache device for a 4K pool) still the correct configuration now?
- Will running
sysctl vfs.zfs.min_auto_ashift=12
(prior to adding it as a cache device) do the right thing for L2ARC, or do we still need to use gnop? - Is there ever a case where you want a mismatch between L2ARC sector size and pool sector size? If no, why isn't this handled automatically (or is it)?