The ZFS Pool on my server was showing degraded state. After checking the SMART status of the constituent drives and finding no problem, I discovered that there’s a bug in Solaris 10.5 where the system reports a growing number of errors and eventually fails the pool. dmesg shows an error unable to kmem_alloc enough memory for scatter/gather list, however, there is actually nothing wrong with the pool. Running zpool status shows degraded state: