Hi, I'm wondering about the impact of using both dom0 and domU's on a server at the same time. I'm worried about the performance impact of running a Mysql server in a domU and now I'm thinking about moving the Mysql part of a LAMP setup into dom0 and running a few Apache guests as domUs. Since the Apaches will serve mostly from an NFS share they won't have much impact on the disk i/o so the database should be able to utilize the local storage without much interference from the guests. The plan is to limit dom0 to let's say 4gb of ram and then use the rest of it for the VMs.
Has anyone experinece with this kind of "mixed" setup (physical/virtual). Are there any known problems with this approach?
Regards, Dennis
On Wed, Feb 4, 2009 at 10:03 AM, Dennis J. dennisml@conversis.de wrote:
I'm wondering about the impact of using both dom0 and domU's on a server at the same time. I'm worried about the performance impact of running a Mysql server in a domU and now I'm thinking about moving the Mysql part of a LAMP setup into dom0 and running a few Apache guests as domUs. Since the Apaches will serve mostly from an NFS share they won't have much impact on the disk i/o so the database should be able to utilize the local storage without much interference from the guests. The plan is to limit dom0 to let's say 4gb of ram and then use the rest of it for the VMs.
Has anyone experinece with this kind of "mixed" setup (physical/virtual). Are there any known problems with this approach?
Hi,
On a performance level it shouldn't make that much of a difference. But a domU will have some more overhead in I/O. So it make sence to run your DB in the dom0.
The only thing to remember is that when something happens to your dom0 the domU's will most likely also be impacted. So that your need to keep in the back of your head.
Regards, Tim
++ 04/02/09 10:03 +0100 - Dennis J.:
Has anyone experinece with this kind of "mixed" setup (physical/virtual). Are there any known problems with this approach?
Dennis,
the dom0 and domU's are both virtual machines on top of the Xen hypervisor. In short, the only difference between the two is that dom0 has additional permissions to control the hypervisor (and thus it has xend and the other management tools). The performance should therefore be equal in dom0 and domU.
All the best, Henrik
Dennis J. wrote:
Hi, I'm wondering about the impact of using both dom0 and domU's on a server at the same time. I'm worried about the performance impact of running a Mysql server in a domU and now I'm thinking about moving the Mysql part of a LAMP setup into dom0 and running a few Apache guests as domUs. Since the Apaches will serve mostly from an NFS share they won't have much impact on the disk i/o so the database should be able to utilize the local storage without much interference from the guests. The plan is to limit dom0 to let's say 4gb of ram and then use the rest of it for the VMs.
Has anyone experinece with this kind of "mixed" setup (physical/virtual). Are there any known problems with this approach?
Go ahead, performance wise there is not much difference. I have a machine which runs 2 oracle instances (in separate domUs) + some other stuff in other VMs Just make sure that your network card has a very good quality. Do not even think about realtek and if possible avoid Broadcom. I've never heard anyone complaining about Intel.
Dennis J. wrote on Wed, 04 Feb 2009 10:03:36 +0100:
I'm wondering about the impact of using both dom0 and domU's on a server at the same time. I'm worried about the performance impact of running a Mysql server in a domU and now I'm thinking about moving the Mysql part of a LAMP setup into dom0
I do not see any problems with MySQL on domUs. Works just fine.
Kai
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Dennis J. -
Henrik Holmboe -
Kai Schaetzl -
Manuel Wolfshant -
Tim Verhoeven