The other day, I was on a customer call, helping with some NAS/netgroup configuration. We were running some tests connecting to a LDAP server to fetch netgroups when I noticed that a netgroup of 100 hosts only returned four IP addresses. FOUR!
There wasn’t anything broken from the storage side. Instead, it was the netgroup – of the 100 hosts, only 4 still existed in DNS.
April mis-configurations bring disrupted summer vacations
Every spring, I like to clean out the garage, clean the grill grates, and eventually, spray off the thick coat of North Carolina pollen that has caked itself on. If I were to let this stuff go all year, I’d probably be featured on some reality show like Hoarders.
The same mentality could be applied to your NAS environment maintenance.
- Removed hosts from the network? Remove them from DNS.
- Removed hosts from DNS? Remove them from netgroups.
- Removed netgroups? Remove them from export policies and rules.
- Changed IP addresses? Make sure those changes are applied everywhere.
If you don’t keep up with your NAS environment, you might be getting calls from your users and/or customers at hours or times you don’t appreciate. Once, on my on-call weekend when I was in support, I had to work a case at 3AM. At the beach. In a hotel parking lot. Stealing wi-fi.
The root cause? Someone mis-configured something.
The fact that I was at the beach and had to be in a hotel parking lot stealing wi-fi was due to my own poor planning. Everyone loses!
Centralize and organize
Some environments still use flat files for hosts, netgroups, etc. While that’s ok, you should start considering consolidating those files into a centralized name service like LDAP, NIS, DNS, etc. After all, it’s a lot easier to make a change on one server than on 600.
If you move away from flat files, you make your life easier, bottom line. And you make your spring cleaning efforts that much more bearable.
What else can you do?
Along with spring cleaning/regular maintenance of your name services, be sure to follow best practices for your NAS environment. For clustered Data ONTAP, I’ve recently published an update to TR-4379: Name Service Best Practices, which covers best practices for many scenarios. For example… Using short hostnames? Don’t. Use FQDNs whenever possible. Shortnames force the DNS client to figure out the DNS zone, which add latency to requests.
Also, pro-tip: If you’re on-call, try to remember not to also be on vacation.