Weblog entry #1 for GhostR
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#1
Xen strategy for a Mail/Webserver
Posted by GhostR on Wed 6 Feb 2008 at 20:57
Ok, this is my setup and my goals just to give the edges.
I'm going to move our dedicated server to a new hoster (hetzner dot de).
They gave me an AMD Athlon 64 X2 5600+ Dual Core / 2GB Ram / 2x400GB SATA no RAID (our current disk usage is 35GB total) / 7 IPs routed.
We currently run an etch web server with multiple domains and an email/smart server for spam filtering. So it's a production server what I still would like to experiment on with XEN because I'm new to it.
What I want to achieve is a xen server with software raid1 so I can separate the services.
I'm not sure at all about the right strategy for this, so here I fire some questions, I would be thankful for some advice.
1. 32bit or 64bit etch?
I'm not planning on running any fancy software outside of the stable repository, and if so I can compile it. And no, I'm not planning on upgrading on more then 2GB Ram total. But I would also enjoy on running 32Bit DomU or vise versa just to be flexible. And no, there is no huge database running on it.
2. What hypervisor to install?
I already found out, always stick with the PAE version because Xen DevTeam doesn't support the old one anymore and it leads to problems.
I'm not planning on running uncustomized kernels so no hardware virtualization needed.
3a. File system Raid Setup?
I definitely want to create a software Raid1, it saved me a weekend on the old server. So should I throw LVM on top? What leads me to my next question...
3b. How to install the guests?
Install them on dedicated LVMs or in Containers? I heard people saying that the container is a bottleneck, what I can see to be true but I really like the idea of a container, easier to move around and to work with or even to backup(yes, I still will rsync the inside of the containers to an external backup space). The server is not that frequented so I can live with some IO lose. I guess the best would be a combination of both LVM and regular sw raid.
Questions over questions, any hints and shared thoughts are very welcomed.
Toby
I'm going to move our dedicated server to a new hoster (hetzner dot de).
They gave me an AMD Athlon 64 X2 5600+ Dual Core / 2GB Ram / 2x400GB SATA no RAID (our current disk usage is 35GB total) / 7 IPs routed.
We currently run an etch web server with multiple domains and an email/smart server for spam filtering. So it's a production server what I still would like to experiment on with XEN because I'm new to it.
What I want to achieve is a xen server with software raid1 so I can separate the services.
I'm not sure at all about the right strategy for this, so here I fire some questions, I would be thankful for some advice.
1. 32bit or 64bit etch?
I'm not planning on running any fancy software outside of the stable repository, and if so I can compile it. And no, I'm not planning on upgrading on more then 2GB Ram total. But I would also enjoy on running 32Bit DomU or vise versa just to be flexible. And no, there is no huge database running on it.
2. What hypervisor to install?
I already found out, always stick with the PAE version because Xen DevTeam doesn't support the old one anymore and it leads to problems.
I'm not planning on running uncustomized kernels so no hardware virtualization needed.
3a. File system Raid Setup?
I definitely want to create a software Raid1, it saved me a weekend on the old server. So should I throw LVM on top? What leads me to my next question...
3b. How to install the guests?
Install them on dedicated LVMs or in Containers? I heard people saying that the container is a bottleneck, what I can see to be true but I really like the idea of a container, easier to move around and to work with or even to backup(yes, I still will rsync the inside of the containers to an external backup space). The server is not that frequented so I can live with some IO lose. I guess the best would be a combination of both LVM and regular sw raid.
Questions over questions, any hints and shared thoughts are very welcomed.
Toby
Comments on this Entry
Posted by Steve (82.32.xx.xx) on Thu 7 Feb 2008 at 19:37
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Personally I agree with you. The overhead of using loopback images isn't terribly noticeable. Having said that I would use LVM for both the dom0 and the guests.
Why? Because it is just more flexible.
For the same reason I would use RAID on the host. It will decrease disk availability, but it gives you slightly increased speed/redundancy depending on how it is setup.
As for the PAE/32/64 bit issues I have no preference. I run 64 bits mostly, but for a mailserver I can't see that it matters too much.
[ Parent | Reply to this comment ]
Yes I did not read the manpages and did an xen-update-image on an new online comtainer guest and now the FS is read only. And yes again I m running the stable version of xen-tools.
Now I know what this is for: (* xen-update-image will now skip Xen guests which are running.)
Why is it like that, ok, why I can sort of imagine, but how would I "fix" this guest(read only issue) if I would do that to a production guest. Just being curiose.
This would habe been such a nice feature to update multiple online machines from the outside but understandable that its no possible.
Now I know what this is for: (* xen-update-image will now skip Xen guests which are running.)
Why is it like that, ok, why I can sort of imagine, but how would I "fix" this guest(read only issue) if I would do that to a production guest. Just being curiose.
This would habe been such a nice feature to update multiple online machines from the outside but understandable that its no possible.
[ Parent | Reply to this comment ]