Any idea what is filling your syslog with these?
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer.local#011IN#011AAAA fe80::85f:1cff:feb1:cca5 ; ttl=120] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer.local#011IN#011A 10.242.170.2 ; ttl=120] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [_device-info._tcp.local#011IN#011PTR HomeServer._device-info._tcp.local ; ttl=4500] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer._device-info._tcp.local#011IN#011TXT "model=Xserve" ; ttl=4500] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer._device-info._tcp.local#011IN#011SRV 0 0 0 HomeServer.local ; ttl=120] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [_sftp-ssh._tcp.local#011IN#011PTR HomeServer._sftp-ssh._tcp.local ; ttl=4500] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer._sftp-ssh._tcp.local#011IN#011TXT ; ttl=4500] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer._sftp-ssh._tcp.local#011IN#011SRV 0 0 22 HomeServer.local ; ttl=120] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [_ssh._tcp.local#011IN#011PTR HomeServer._ssh._tcp.local ; ttl=4500] not fitting in legacy unicast packet, dropping.
Jan 28 21:14:25 HomeServer avahi-daemon[8523]: Record [HomeServer._ssh._tcp.local#011IN#011TXT ; ttl=4500] not fitting in legacy unicast packet, dropping.
Difficult to wade through all that.
Since you have dual parity your data is probably going to be OK.
The disabled disks are not reporting SMART. Most likely a connection issue. Check all connections, both ends, SATA and power, including any power splitters. Then reboot and post new diagnostics.