Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am thinking of getting a 256MB server on XEN but not sure is it capable of handling this setup: Varnish + Nginx + Eaccelerator + PHP-FM + MySQL + Mail/FTP?

I've tried this setup on OpenVZ and it was partly disastorous, especially with varnish in the equation, i've heard that XEN is better at memory management, sometimes shaving off 50mb or more in comparison to OpenVZ setups...

if anyone has any helpful suggestions / input please let me know


share|improve this question
up vote 1 down vote accepted

openvz 256mb ram != xen 256mb ram

with xen you get 256mb ram when it says 256.

with openvz it depends ... it comes down to what the provider gives into the configuration. for example into your vas you can see 256mb but when you do a memory allocation of 128mb you fail and that is because the memory model on openvz is different it uses a soft barrier and a hard one also comes into equation the total memory of the system. for example on a host with 1gb ram you can have 4 vps each with 512mb ... if you want to learn more about it google it.

as a conclusion if you had 128mb ram burstable to 256mb ram with openvz with xen you get double if you have 256mb so your setup should work. how well it will perform it depends by your traffic.

share|improve this answer
thanks for the answer, i still feel weary about getting only 256MB RAM-- 512 seems to be the more comfortable number – Trazx Jan 8 '11 at 17:03
512 is beter anyway but if you can't afford it ... – silviud Jan 8 '11 at 19:34
Follow up question: If the host does indeed keep true to their word with OpenVZ RAM, what other differences are there from XEN performance-wise? – Kevin Duke May 9 '12 at 18:01
openvz is lightweight as it doesn't do real virtualization as xen - however on some cases xen is very fast as well (with the newwest drivers etc is quite fast) but depends by provider. it depends as well what do you mean by performance ... memory (xen) is better as you have preallocated. – silviud May 11 '12 at 2:26

I think it all depends on how many users you want to be able to handle. Just at a glance, it seems like just running all those things at once will take up a sizeable amount of RAM, so I would say that with anything more than like 10 users you will start to run into performance issues.

share|improve this answer
+1 it should work but it will be a tight fit – Hubert Kario Jan 8 '11 at 15:23
you mean 10 concurrent users? or do you mean 10 separate users (websites) on this setup? – Trazx Jan 8 '11 at 16:50
10 concurrent. Also, I wouldn't run more than 2 sites on that setup. – BenGC Jan 8 '11 at 16:53

As an aside; if you're paying anywhere near $20/usd, check out Linode You can get 512Mb for that price.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.