December 28th, 2011, 12:28 AM
Be DNS failsaif , how ?
recently our server faced 24 hour downtime because of DNS issue
we are using IBM cloud service and as IBM cloud so not provide DNS service we had to opt for third party DNS service
we are only using A record domain mapping to IBM provided IP
so now I don't want to get into this situation again and want some backup service.
So I was thinking can opt one more dns service and make a A record entry again with same domain ,
or there are any other way to be fail safe ?
December 28th, 2011, 09:02 AM
When you configure your domain name you have to specify a minimum of two nameserver records. If these nameservers point to different servers, then if one goes down the other will be used.
December 28th, 2011, 05:37 PM
A quick thing to note is that if a Primary fails, the Secondary will only remain authoritative for the length of the Expiry field in the SOA. However if you have two nameservers for the domain running in Master mode on both, it should answer authoritatively indefinitely (as long as the server is up of course...). The downside to that is you have to manage each one seperately since there are no xfers.
Expire: How long a secondary will still treat its copy of the zone
data as valid if it can't contact the primary. This value
should be greater than how long a major outage would typically
last, and must be greater than the minimum and retry
intervals, to avoid having a secondary expire the data before
it gets a chance to get a new copy. After a zone is expired a
secondary will still continue to try to contact the primary,
but it will no longer provide nameservice for the zone. 2-4
weeks are suggested values.
December 29th, 2011, 12:09 AM
name server did not fail but my A record stopped working and that's why my site went inaccessible,
and yes In my control panel I have given two NS provided by hosting company.
I want to to totally eliminate the dependence on single NS hosting but want to make a same A record entry to second webhosting company also so that if that name server fails other name server take over ,
I want to point out here that I do now own any NS just using webhosting provided service
December 29th, 2011, 09:13 AM
What exactly do you mean by the A record stopped working? If the record was incorrect but server still up, DNS functionality would still be operational and the incorrect record would be cached elsewhere. Lowering the TTL will increase the query rate but will reduce fallout from an incorrect record. If the servers failing isn't your issue, having another NS somewhere might not help you.
December 29th, 2011, 11:14 PM
I assume A record was the problem , because I have 5 domain registered with same hosting company , but only one domain was not resolving from any where in the world (at least 4 country)
and A record was correct as i was working fine from last 3 months
So I registered a complaint and they said we have refreshed the dns , and with in hour it started working before that it was down for 24 hrs
December 29th, 2011, 11:22 PM
If the server never went down, it sounds like the zone or maybe just that record got messed up. There's not really a backup you can have in DNS if it was due to a mistake they made. You may want to see if you can get more information on what happened and what they did to fix it. Even if you hosted alternate servers somewhere else, that may have been no help for your problem. Without knowing exactly what the issue was it's hard to give any advice. If it was the only time it happened, it could have just been some weird fluke. If this is frequent, you may want to switch providers.
December 29th, 2011, 11:39 PM
Yes I remember she was saying something about zone file missing
This happened first time , but I have a pressure from my bosses to have a plan B if this accrue again.
December 30th, 2011, 12:10 AM
Yeah if something was wrong with the zone, the slave server probably had the same issue. If you had a clone set of servers somewhere else on standby, you would still have downtime switching to them. You would have to change the name servers at the registrar and that change can sometimes be quick but can sometimes take hours. You then have to make sure both sets of servers are matching in the data they have.
My recommendation of spot requests of anything is Amazon.com's hosting services. I have personally used their EC2 service to set up emergency servers. With EC2 you get command line access and can build your own server from scratch if needed. A more simpler system they have is their Route 53 service for DNS. That may be something for you to look in to as a backup if you wanted. I don't use them as a constant host but their pay as you go (per hour) plans have been good in a pinch. Route 53 pricing is in the amount of queries.
That may be over complicating things though. Getting someone to monitor the DNS (or a program to alert you) is going to be a simpler more realistic option. That way you can catch the problem quicker. I've never used a third party program for DNS monitoring but I'm sure one exists somewhere.
December 30th, 2011, 01:04 AM
thanks for the suggestions ,
I already have a monitoring service for my site already but may be because of 25Dec , SMS service got choked and I did not get any sms , and it went down for almost 12 hrs without knoing any one as it was holiday no client complain also but my site states went very down
thank u again for ur prompt replays