Forum OpenACS Q&A: Another OpenACS hosting option

http://www.cornerhost.com

(Disclaimer:  I provide "developer" OpenACS instances @ $79.95 per month at www.zill.net)

I'm the guy that runs cornerhost (thanks for the link, Dave).

I don't have a page about OpenACS because I never thought about
hosting it specifically until Dave asked. I'm not an OpenACS pro by
any means, but I've read Phil Greenspun's book and have a basic
idea what it's all about.

In general, I install the basics (tcl, databases, etc), and if you want to install a server of some sort, then I'll assign you the
ports you need, and then you're free to configure it any way you like.

Whatever you install on your own does count towards your space usage. The demon account comes with 250MB, and additional space is 25MB/$1.

Question: is it possible to run a single AOLServer for multiple users? Can you develop comfortably without having to restart the server periodically?

Thanks!

How did you come up with the ~200MB figure? A quick du for a fresh OpenACS that I have (RPM) is ~15MB, and the Postgresql data directory is ~36MB (only the ACS database is present, plus the Pg system database)

Michal, I assume the Postgresql installation itself (not the database space for OpenACS tables) wouldn't count towards the disk quota then?

Thank you

One of my clients uses 120MB, but that is because I (God or root, what is difference?) pruned their install down and keep on top of their web logs ( I gzip them with gzip --best).

When you keep in mind their disk space as used by Postgres, which appears to be about 100MB (they have a lot of content), you get 220MB.

Add CVS usage, other stuff you might want to keep around, etc. (they do all their development elsewhere) and you can see that it easily gets to more than 200MB.  Oh yes, you want to create a backup or two of the Postgres DB if you are trying out new things.

Another client does do light development on the system (CVS) but does not have as much data in the db.  They do use the file-storage module.  Their disk usage is 140MB, plus a small db footprint of about 20MB.

If you are being careful, yes, you can have stuff under 200MB - by putting your other files somewhere else; but that doesn't give you much room to "move around" as it were.

The UML kernel has a nice feature called Copy On Write (COW) which lets you start with a base filesystem image file, and then any incremental changes you make are written to a different file. This means it is easy to share a common read/write filesystem among lots of virtual machines.

My idea is to run a bunch of these virtual machines on a single physical host, and to have the underlying host run Postgres. The virtual machines would each run their own AOLserver process, and could communicate to the host postgres via TCP. I did some rough timing measurements, and running gcc to compile AOLserver inside a virtual machine was about 1/5 the speed of the compile on the host. This leads me to estimate that general performance of a virtual server will be about 1/5 of "native" execution. I am not sure how many virtual machines can comfortable run on a single physical host, but if they are lightly loaded, I would guess that it is roughly RAM limited, and 2 GB of main memory could probably host up to about maybe 50 or 100 virtual machines. They are of course all sharing the same CPU, RAM, and disk, so when I say lightly loaded, I mean it. Still, for casual use like personal web sites, this might be quite adequate, considering that I used to run a web server on a 50 MHz Pentium CPU.

I think the advantage is that you have a real "machine" all to yourself, you can have root access, you can install modified binaries of the server, you can compile extensions to the kernel even. I'd be interested to see if anyone tries to start selling leasing of these VM's rather than these sort of hacked up shared servers.

That coupled with some grsecurity patches and you get around some of the security issues introduced by SKAS mode.

Or, there's always BSD's jail which is fairly efficient.

For all the searching i've done here, these are new for me.

I *really* like vservers for development space and testing.  The isolation is very cool, and the ability to blow away a vserver and replace it with a new one from the template is handy.

Of course, you need a vserver-enabled kernel to do it, but I've moved vservers between P4's, Athlon XPs, Durons, Celerons (ugh), etc.