Symptoms
Dell EMC Unity Array is showing an Alert Status in the GUIMultiple File Systems exported using a NAS Server are showing as status degraded.NAS Server in the Unity GUI is showing in a degraded state.From Alerts-----------------------------Time (UTC ): 11/24/2016, 11:28:22 AMSeverity : Error Message ID:14:603b8Message: DNS servers configured for the DNS client of NAS server examplenas01 are not reachable.Description: DNS servers configured for the NIS client of the NAS server are not reachable. Check network connectivity. Ensure that at least one DNS server is running and the storage system can access it.Acknowledged: No-----------------------------
Cause
DNS Servers defined in the NAS Server Configuration are not reachable by that NAS server.From the Dell EMC Unity service shell ping, nslookup or dig can be used to perform some checks.PING ExampleWhere NAS Server is assigned IP 192.168.1.xxx and DNS Server is 192.168.2.xxxUsing ping with "-I" to specify the NAS Server NIC to send the ping from.service@none spa:~> ip addr show | grep 192.168.2.xxx inet 192.168.1.xx/24 scope global secondary eth10service@none spa:~> ping -I eth10 192.168.2.xxx -c 2PING 192.168.2.xxx (192.168.2.xxx) from 192.168.1.xx eth10: 56(84) bytes of data.64 bytes from 192.168.2.xxx: icmp_seq=1 ttl=127 time=1.02 ms64 bytes from 192.168.2.xxx: icmp_seq=2 ttl=127 time=0.916 ms--- 192.168.2.xxx ping statistics ---2 packets transmitted, 2 received, 0% packet loss, time 1000msrtt min/avg/max/mdev = 0.916/0.970/1.024/0.054 ms service@none spa:~>
Nslookup Example:Using a specific DNS server to run the query against.service@none spa:~> nslookup> server 192.168.2.xxxDefault server: 192.168.2.xxxAddress: 192.168.2.xxx#53> examplenas01;; connection timed out; no servers could be reached> exitservice@none spa:~>DIG Example:service@none spa:~> dig @192.168.2.xxx examplenas01; > DiG 9.9.9-P1 > @192.168.2.xxx examplenas01; (1 server found);; global options: +cmd;; connection timed out; no servers could be reachedservice@none spa:~>
Resolution
Connectivity to DNS Server(s) needs to be checked and that the DNS Server is responding to requests.For reliability and performance multiple DNS should be defined for use by the NAS Server to avoid a single point of failure in the environment.When multiple DNS servers are defined for a NAS Server, if one is not responding the status in the GUI is shown with a white "i" on Blue Circle, = OK (But).
This indicates: "The object is operating normally but there are potential issues".Reference:Dell EMC Unity Inline Help >> Search "health status" and select > About health status
