ricardo at americasnet.com
Sat Aug 5 19:09:06 BST 2006
Thank you for your comments.
More comments below...
>> Just wondering if that would work...
> Short answer: yes :)
> You will need to solve a few minor problems, as you'll end up with a
> system with a pair of VIP addresses for your clients to connect to.
> That means you'll need to do something like DNS round-robin; in turn
> that means you'll need to endure the outage if (for example) one of
> your servers has to be taken (or goes) offline and stops responding.
So you mean that round-robin DNS won't really work? I've always wondered how
resolution of round-robin DNS works... do lookups always swap between the
different IPs with each subsequent lookup?
So for example, if I have round-robin DNS jumping between servers A/B, and A
goes down... if a client resolves the hostname to A, it will fail to
connect, then if it retries, will the hostname next time resolve to B?
> Alternatively you'll need something to manage both the LVS and HA
> aspects of the system, like keepalived or heartbeat.
Are these really necessary? If all I'm using it for is for the load
balancing, and LVS is capable of detecting a server going down, it will
simply direct connections to the alternate server. What would I use
keepalived or heartbeat for?
> You will also need to solve the potential problem of both servers being
> configured to handle both VIPs as both LVS director and realserver -
> this one can tie you in knots very easily. I usually manage it with
> fwmarks on the input interface (the one facing the clients).
If I understand correctly, the realservers are the DB servers. The LVS
director is on the app server, which directs connections to one of the 2 DB
servers. Why would there have to be any sharing of VIPs? I don't think
either of the servers would be both director and realserver, would they?
More information about the lvs-users