Your problem is that your pool uses BIOS controlled device names (sda, sdb, .. etc). When you remove your SSD the remaining disks in your pool changes names. Eg SSD was called sda and when removed another disk becomes sda since disk naming always starts with sda. Problem is that ZFS uses static name assignment so it expects sda to always be the pools l2arc/log and not a normal pool member. See http://zfsonlinux.org/faq.html#WhatDevNamesShouldIUseWhenCreatingMyPool