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Jon Molin wrote:
>
> Hi list,
>
> I'm considering to use LVS with two servers. These will be two
> webservers, i.e. only httpd running there. Now my problem is that I just
> want these two servers as I've got very little space for them, I can't
> fit in a third (or even forth) server to use as director. I read in the
> howto chap 15 about localnode, and it says there '(We rarely hear of
> anyone using this.)'. Is there a special reason for not many running it
> or is it just that ppl generally has more servers?
There may be several reasons :
-director running on antics (pentium 75MHz, ...)
-huge traffic => need for a dedicated director
-keeping the configuration simple: one task per server
Anyway, I've had the same problem than you and it turned out that LVS
works fine with only two servers.
>
> What I want is as stated in ultra monkey 'high capacity, highly
> available, load balance service' but only with two servers. One being
> master, the other slave checking heartbeat of the master. As I might
> somwhere in the future add a third server I want the sollution to be
> scalabale and therefor it sounds like LVS (ultra monkey) is what I want,
> if it works fine with only two servers.
It normally should be scalable with decent material. PIII 700-800 MHz
seems to be largely enough : as I posted in this thread, the cost of 250
hits per second on a regular linux router is 0.3% of the system power
(CPU and IO).
Even considering a strong overhead due to lvs, like bringing the cost up
to 1% of the system power, it still seems scalable to 5-10 servers
easily.
For the high availability, you should have a look at keepalived
http://keepalived.sourceforge.net/
Regards,
Jacques.
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