>>> turn off readahead. ZFS' own readahead and the kernel's clash - badly. >>> Turn off kernel's readahead for a visible performance boon. >> You are probably not talking about ZFS readahead but about the ARC. > > which does prefetching. So yes.
I'm taking notes on this so I want to clarify, when using ZFS, readahead in the kernel should be disabled by using blockdev to set it to 8? - Grant