Re: [squid-users] LVS/TUN or LVS/DR

On Wed, 9 Feb 2005, Askar wrote:

> sorry my ignorance, I don't really have good idea abotu LVS/TUN or LVS/DR.

LVS/DR is generally preferrable over LVS/TUN as it doesn't require any
special support in the cache server OS (just a carefully planned network).

LVS/TUN requires a appropriate tunnel to be configured on the cache server
OS, and in addition have troubles with large packets if your network does
not allow for jumbo frames (most don't). For proxies you only need to look
at LVS/TUN if you have a router between the LVS director and the cache
server and you are doing transparent interception proxying as LVS/NAT is
incompatible with interception.

LVS/NAT nearly always works for proxies, except if you are doing
transparent interception proxying. LVS/NAT is by far the easiest to use.

> These days we are thinking seriously going LVS for our three cache servers
> that is now we have to put a load balancer in front of these three cache
> servers.
> which load balancing algorithm is good ?

Normal proxying, or transparent interception? This is important for
selecting the proper forwarding method (see above).

Do you have a NAT device after the proxies, or are they directly connected
to the Internet? If you don't hae a NAT after the proxies then you'll want
to use a sticky balancing scheme where the same user is preferably sent to
the same proxy for his session. If you have a NAT after the proxies any
load balancing scheme is fine.

If you are doing interception caching then there is also a special load
balancing scheme based on the destination address, optimizing hit ratio.

Regards
Henrik
Received on Wed Feb 09 2005 - 01:57:04 MST