Different architectures for cPanel-based boxes?

[samsam]

Hi:

I was wondering how flexible cPanel and WHM were in running all the services they needed to run. This train of thought was prompted by the continuing discussion of performance issues in these forums - how many users can a Dathorn account support, how much resource utilisation is OK etc etc. Until the cows come home.

It always amazes me that with the kind of hot, modern servers that Dathorn has around the place - 4 CPU 2GHz Xeons with 1-2BG of RAM, thousands of GB of storage, SMP operating system etc - that the issue of performance should keep on rolling on, and sites keep on getting suspended for hogging the server etc etc.

That is serious hardware you're talking about, even if each server may be serving hundreds of sites. Probably 4 years ago, you could have run Yahoo on a box like that These sort of problems that users are always having should not be happening when one has access to such super-servers, unless something was not optimal.

On this point, I got curious about what architecture cPanel and WHM needed to run on, because it strikes me that it is probably not always great from a performance and stability point-of-view to have cPanel based boxes running the way they seem to under most hosting environments.

In looking at activity on my current Dathorn cpanel server, you can see the problem at work: most of the time the big hogs are not Apache, but the SMTP server and MySQL, who have to continually fight with Apache for access to the limited resources of the system. So the headroom for Apache's performance is considerably lowered on that box because of this. And vice versa - MySQL has to fight with Apache, Exim has to fight them all, etc etc etc, and so each core service is performance compromised.

In fact, it seems a standard server box running cPanel/WHM runs everything but the kitchen sink on it - Exim SMTP, MySQL, DNS server, Apache w. PHP etc etc. It certainly looks that way when you are viewing server activity using top.

Unless I am wrong, probably each box in such a hosting environment - eg cpanel 32. 33, 34 etc - run pretty much the same build and software image. So to add users, and capability, you need to clone another cPanel/WHM box and add it to the rack, with all of those services running from that box in the same way they run off each of the others.

30 servers in the rack = 30 instances of MySQl, 30 DNS servers, 30 SMTP servers etc etc.

In a MS Windows server hosting environment, you'd never do things that way. Licensing costs would kill you, for one reason (30xIIS, 30x web-visible MSSQL etc = mucho big $$), but you also wouldn't do things that way because it performs poorly to have a whole fleet of general purpose boxes, and it also is an admin/security headache.

You'd set up things in a more partitioned way, generally (depending on the size of your operation). You'd have a bunch of servers just doing web serving and scripting, you'd have a separate big beefy SQL database server or two, you'd have a separate SMTP server, also separate DNS servers, and in the middle of it somewhere a backup system, and other bits.

All these machines would be able to talk to each other, of course, usually across your gigabit backplane or something, and from a user or developer perspective it would all be transparent, even the database stuff. Sometimes you could also even put different machines in different security environments too - eg have the SQL server(s) physically and logically firewalled off from the web server(s), which is very nice to do.

In these environments you can then also really tune specific machines to do specific jobs really well, and cut out of them all the other crap that would normally run on them and rob them of performance.

Your web server can be optimised to serve pages and run scripts efficiently and securely, and that's all. Ditto your databases server(s) - they could be tuned and specced just to be excellent at being database servers. Same with your SMTP server, DNS box, user authentication etc etc.

These environments I think perform and scale better, can be more managable and secure, and may even be more cost effective too.

To cut a long-story short - when a web-host sets up a cPanel/WHM operation, can it support this kind of architecture?

I haven't trawled the web or the cPanel site yet for any info on this, but thought I'd ask here, because I suspect some people on Dathorn have probably thought about this issue.

It is just an academic kind of question, but I was curious about it.

[KyleC]

Absolutely it can be setup that way, unfortunately it is a pain to do with cPanel, most of it would have to be done by hand, by the admin AND the customer. the poor planning and architecture of cPanel make it allomost impossible.

just recently cPanel has be trying to implement shared mysql server

one control panel i am impressed with is HELM for Win32
instead of this:


you have this:



all controllable from 1 root control panel, its genius and it works pretty well. i have seen it implemented. This is expensive to setup and has a high start up cost.

cPanel is a sad offering for its price. Unfortunately it is the most popular right now and is demanded my customers.

[samsam]

Thanks for that info - that's exactly what I was talking about.

And that Helm info (and those diagrams) was good - I'll toodle off and have a look at that site now. And I also think they are the guys whose control panel lets you easily host/offer to customers both Windows and Linux sites from within the one control panel, if memory serves.

I suspect that although this server arrangement may have higher start up costs (you need to do a fair bit of planning and server engineering beforehand, for one thing) using commodity boxes and license-free open-source stuff for all the servers should help control costs. And once you have the core structure built, maintenance and expansion should, I suspect, be cheaper than the conventional model. But the main thing, and I hope Helm has some advice on this, the whole infrastructure should perform faster!

It is interesting, BTW, the absence of any security services or concepts in the Helm diagram of their server farm

Although it is just a high level overview, I still would have pencilled in some security segmentation of the servers, and stuff like a central syslogging server, a box or two doing network based IDS, and of course a border and DMZ firewall.

Other bits like a router and switch or two would also need to be there..

I better go over to Helm and have a look.

It would be interesting and I think positive for cPanel to be able to move in this direction. The current architecture doesn't seem to have much going for it other than initial simplicity.

[KyleC]

yep, the best thing about helm is that the usage of multiple servers is transparent to the user.

as for including other things in helm and that diagram, i think IDS and firewalls are part of the datacenter platform, not the hosting control panel layout. we have to draw the line for CP software somewhere. But a central syslog server would be a very good idea.

i would use this CP for my windows boxes in an instant, but i have no need for its reselling features... the next major release it due out before the end of the year, i cant wait to see what they do with it. the cp interface is not as easy to use as cPanel, thats one thing i would like to see improved.

[openbox]

cPanel was developed as a budget control panel software, hence its small scoped setup. The things you are discussing are routinely done in "big" operations. Psoft's product does exactly what you're talking about, not that I'm calling H-Sphere a "big" control panel.

[samsam]

Another budget web-host uses clustered architecture

Without meaning to give them a plug here, and simply from a research point of view, I just discovered another budget ($7/month) standard (non-reseller) web host who has implemented the sort of clustering architecture we are talking about here,

POWWEB link

As they say:

In a "Conventional" [ie cPanel/WHM] architecture, a single computer runs the web server, FTP, WWW, e-mail, Database, and etc. The weakness of this architecture is that should one service be afflicted with any problem, all other services can be detrimentally affected as well. [Amen!!] This is because the services all share the same resources.

"Clustering/ Load Balancing" Architecture

In our "Clustered/Load Balanced" architecture, each service is provided by multiple dedicated machines. Should one machine becomes non-operational at any time, other servers would be available to handle the extra load, avoiding any downtime for our customers

This very sensible architecture seems to have let them scale their users hugely (13,000+ accounts), without dropping account features and options, and performance either, from what I can tell.

Geeze, they even offer 5GB *a day* transfers. And include daily/weekly and monthly backups of both MySQL and site content as part of the $7/mo

I think that this architecture must make offering those sort of services at those price points more cost effective.

On an un-related note, they also have some good software running a kind of 'Resource Center' within which their user forum resides, but which is also structured as a kind of library.

http://resources.powweb.com/index.php

It is quite good. I wonder what PHP script it is based on. I like the tabbed interface. Maybe one day Dathorn could evolve something similar.

[Jonathan]

I'd rather Dathorn stay as good
as they are now, and not drive costs
up by implementing new systems, EVEN
if they were better.....

[samsam]

I am not saying that for multi-domain reseller, Dathorn are not good value. Clearly they are.

And as an ex-IT guy, I agree that if something is stable and works most of the time, usually it's best not to play around with it too much

But I think over time, for growth and performance purposes, lots of cPanel/WHM shops will probably need to evolve towards these sorts of architectures, inc Dathorn but also others, of course.

Even now you can see the limitations of the current cPanel/WHM approach. I think the cPanel guys themselves know this too. It just doesn't scale.

Of course, it's all academic for me.

That is, until they day I get pinged by Andrew for one of my accounts hitting a server usage limit

[DomainDog]

I thought we weren't supposed to put links to Dathorn competitors in our posts.

[samsam]

Just because they are a webhost doesn't mean they are a competitor.

They are a simple 1 domain per account end-user hosting shop, which is a very different market to the one Dathorn serves, I would have thought.

Compared to Dathorn, on that basis, they aren't even particularly good value.