Hi everyone, I would like to have a suggestion about the best distro for my VPS in order to have the best performance and stability.

Now I have a VPS 540 running Tomcat for J2EE applications with a MySQL db engine; it's my only VPS so it runs all my services: mail (postfix+dovecot), application server (tomcat 6.0.20) and database engine (MySQL 5.1.42).
In the future (according to business growth...) I would want to separate the services in several VPS, but so far one VPS is doing everything.

The distro I choosed is Debian 5.0 x64 (latest 2.6 Stable (2.6.18.8-x86_64-linode10)) and my doubt is just about the two possible options: stable with kernel 2.6.18 or paravirt with kernel 2.6.32.

Which are the differences? Which is the best one for my applications (J2EE)?
Now I'm using the "stable" version without any problem, but I'd like to know if I can have performance benefits with the other distro (paravirt).

Thank you in advance for every suggestion.

Raffaele

First some terminology: Debian 5 is the distribution, and the 2.6.18.8 vs. 2.6.32 thing is the kernel

If you're running on a smaller VPS (e.g. anything smaller than 2 or 4GB of RAM or so), you'll probably want to use 32-bit instead of 64-bit if at all possible: all other things being equal, the 64-bit architecture wastes more RAM. This will require re-deploying from scratch, but it's something to consider.

As for the kernel choice, it depends on your application... 2.6.18.8 is a much older kernel, but uses a different way of handling Xen than newer kernels. A year or two ago, it was certainly more stable than the newer kernels under Xen, but the situation improved drastically over the past year. Some report it's faster, a few report it's slower, and many report it's the same. You'll have to try with your workload.

(Also note that some distributions, including Ubuntu 9.10, Slackware, and Arch, require the newer kernels. If you can boot under 2.6.18.8, then Debian 5 is not one of them.)

Debian 5 works nicely with 2.6.18.

Sorry... I merged two meanings in one word. I was talking about the kernel.



I want a x64 distro because my development environment is a x64 UNIX, so I prefer to suffer a little memory waste having the same environment for production and development.
However, can you give me a more precise indication about the memory waste between 32 and 64 bit version?

Thank you and sorry for the delay in my answer.

Yeah, binary compatibility is a reasonable reason to take the hit and go with 64-bit.

The memory consumption differences will vary depending on circumstances, but http://journal.dedasys.com/2008/11/24/slicehost-vs-linode has a couple graphs. They found 32-bit to use roughly 77% the memory of 64-bit.

I'm sure there's more data out there too, just can't remember where it is