[AusNOG] Experiences with web load balancers

[Shaun Dwyer]

No one seems to have really mentioned open source LVS based solutions.

In many clusters I've built I've used a pair of Linux machines and in-kernel LVS, coupled with a user-space application such as heartbeat+ldirectord, keepalived, ultramonkey, etc etc.

http://www.linuxvirtualserver.org

At the very least this solution on some fairly modest hardware will perform extremely well for a very very busy hosting site for mail, web and FTP traffic.

I've played with the Barracuda load balancing boxes, and they seem to be largely LVS with a web interface on top. No apparent ASIC accelleration; all software.

Where I currently work, we are using this to balance the load for some very busy DNS, web, and mail services, along with some other random services. Done on a pair of Dell R300 servers spec'd up as 'entry level'. They don't even break a sweat.

In some cases, im sure LVS will be more flexible than a rigid commercial solution ; for example, firewall based packet marking to classify packets into a particular load balancing group - makes services that use multiple ports a breeze to get working and properly balanced.

Worth a test before dropping a bomb on some commercial software/hardware.

Cheers!
-Shaun



On 16/01/2010, at 7:34 AM, vak wrote:

> My 2c worth.
> 
> Love F5 - particularly when "protecting" legacy apps - app health 
> checking is really strong (check out iRules on v9 firmware).
> 
> But yes, expensive.
> 
> David Hughes wrote:
>> Hi
>> 
>> My hands-on experience covers Foundry, Cisco, and F5.  We run a lot of F5 BigIP's at present.  They are an amazingly capable and flexible device.  There is so much functionality under the hood that you probably would be hard pressed to find a corner case that couldn't be handled.  And they perform quite well.
>> 
>> BUT, and there's always a but, they have major failings too :-
>> 
>> 1. Their software QA is bad.  We've had more show-stopper bugs than I'd care to recount.  When we find a stable code version we tend to stay there until it's nolonger supported.
>> 
>> 2. Capacity management and forecasting is very, very difficult.  Virtually impossible.
>> 
>> 3. They don't come cheap.  Must admit the current generation of boxes has helped as each level in the product set has jumped to the performance of the level above from the last model range.
>> 
>> 4. Their maintenance costs are mind blowing.  TCO of these boxes is very significant.
>> 
>> I have a love / hate relationship with the F5 kit :-)  I have done some amazing things with them (like advertising /32's for VIPs directly off the loadbalancer via BGP and re-routing services between datacentres on server failures etc) but the reliability and maintenance charges make me want to look elsewhere regularly.
>> 
>> If you don't need the high-end functionality that these boxes offer then something like the current ServerIrons may be a more cost effective solution.  Haven't played with ServerIrons for quite a few years now so I'd be interested if anyone has feedback on the current models and code.
>> 
>> 
>> David
>> ...
>> 
>> 
>> On 15/01/2010, at 9:12 AM, Michael Richardson wrote:
>> 
>> 
>>> Hi list,
>>> 
>>> We've all been so political lately... maybe this will help get some
>>> technical talk back up in the list...
>>> 
>>> I'm wondering if anyone would be able to make some recommendations on their
>>> experiences with web-farm load balancers. In a previous job I'd installed
>>> and configured some Cisco ACE 4710s, and found them to be pretty solid, but
>>> now I'm in the market to buy some more and I'm wondering if there are better
>>> options out there. I'm a CCNP, so I'm leaning towards Cisco, but the 4710s
>>> aren't really Cisco boxes anyway, just re-badged Arrowpoints.
>>> 
>> 
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