Hello, I am using zfs for a while now. I am not using it for / but for /var and my media collection. PORTDIR is /var/portage so portage files are on zfs too.
This resulted in portage being incredible slow. eix-sync took ages, emerge - auv world gave you enought time to prepare a meal. And eat it. Until I turned off readahead. Dear Gents, if you are trying out zfs, make sure you turn off readahead for your zfs disks. On a related note: increase readahead for your none-zfs SSDs. And make sure the no-op io-scheduler is used for them all. -- #163933