Re: nscd and DNS cache

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 05/17/2012 12:28 AM, Greg Woods wrote:
> On Thu, 2012-05-17 at 00:13 +0800, Ed Greshko wrote:
>>  when you do a look up on www.cnn.com it will return 4 IP
>> addresses.  Now, since bind would have that in its cache it wouldn't have to send out
>> a query.  What I don't know is if an application would make a request would the list
>> be returned in the same order every time to the requesting application?   In other
>> words, if the TTL is not set low, would that defeat the round robin technique.
> Unfortunately, there is no guarantee that a client resolver will
> actually use the IP addresses in the order they are presented by the DNS
> server. Nothing in the DNS spec requires them to do so.

Yeah....  I know there is no spec...  I'm just expecting the clients to be "dumb" and
take the first one in the stack.  :-) :-)

>
>> Interesting things to investigate.....if I really had the time.
> My experience says that DNS round robining is actually a poor method of
> load balancing. I'm surprised to see a large site like CNN resorting to
> this (if that's really what they are doing this for). Perhaps in
> combination with a low TTL and a modified DNS server, they can send out
> a completely different set of IPs every few minutes, and achieve a sort
> of crude load balancing that way, but I think load balancing works
> better if you just send out a single IP and use a load balancer that you
> can control, such as LVS (Linux Virtual Server) that can farm out
> incoming connections to a single virtual address out to multiple real
> addresses.

Yes...  I suppose one also has to ask if the load balancing is meant to be server or
network balancing.


-- 
Never be afraid to laugh at yourself, after all, you could be missing out on the joke
of the century. -- Dame Edna Everage
-- 
users mailing list
users@xxxxxxxxxxxxxxxxxxxxxxx
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org


[Index of Archives]     [Older Fedora Users]     [Fedora Announce]     [Fedora Package Announce]     [EPEL Announce]     [EPEL Devel]     [Fedora Magazine]     [Fedora Summer Coding]     [Fedora Laptop]     [Fedora Cloud]     [Fedora Advisory Board]     [Fedora Education]     [Fedora Security]     [Fedora Scitech]     [Fedora Robotics]     [Fedora Infrastructure]     [Fedora Websites]     [Anaconda Devel]     [Fedora Devel Java]     [Fedora Desktop]     [Fedora Fonts]     [Fedora Marketing]     [Fedora Management Tools]     [Fedora Mentors]     [Fedora Package Review]     [Fedora R Devel]     [Fedora PHP Devel]     [Kickstart]     [Fedora Music]     [Fedora Packaging]     [Fedora SELinux]     [Fedora Legal]     [Fedora Kernel]     [Fedora OCaml]     [Coolkey]     [Virtualization Tools]     [ET Management Tools]     [Yum Users]     [Yosemite News]     [Gnome Users]     [KDE Users]     [Fedora Art]     [Fedora Docs]     [Fedora Sparc]     [Libvirt Users]     [Fedora ARM]

  Powered by Linux