High-availability second server

[coolemail]

Forgive me if this is a newbie question.

We have Plesk 10.2.0 on CentOS5. We also have a second, older server also with CentOS5. I want to set up 2 things:

1. Linux High Availability between the 2 servers so if one went down everything would automatically flip to the second server which would be up to date with emails, websites etc. and avoid down-time. Lots of questions come from it:
- surely for a failover server we di not need to purchase a second Plesk licence? They are not cheap, and we pay hundreds of dollars each year to renew our licence (unlimited domains). Surely others doing this are not purchasing additional licences just for the failover peace of mind?

2. We have an external mx backup which has little/no spam protection. I would like our mx backup to be on our second server if that is possible as well, without prejudicing serial 1 above.

3. I would like us to be doing our own secondary name servers on the second server - most likely linked to serial 1 above.

Please could the experts guide me and advise on best practice to achieve the above.

 

[IgorG]

Officially we haven't any supported solutions for Linux High Availability between the 2 Plesk servers.
You can try to deploy this system but I'm not sure that it is possible.
Regarding license question I can suggest you move somehow whole /etc/sw/ directory between servers.

 

[coolemail]

Thank you, as ever, for your response Igor.

Are you saying that if the primary server went down and everything switched to the secondary server, if the /etc/sw directory was the same then the licence would make available the web interfaces for Plesk etc.?

If any other experts read this, I would appreciate knowing what the best practice is to cover a primary Plesk server going down and having some sort of high availability between 2 servers.

 

[IgorG]

Note that you can't have absolutely identical Plesk licenses on both servers simultaneously because it will be detected by Parallels Key Administrator system and license will be terminated.

 

[coolemail]

Thank you for that warning, Igor. If the second server is just "dumb" as Linux HA until needed, presumably it would not broadcast as it would not be used until the first server goes down.

The annual cost for Plesk licences is not cheap and to purchase a second one "just in case" would be unaffordable. I wondered if there is a brst practice thing that I have not realised on how we can have failover.

I guess we could have the second server take over but with no Plesk CP access because there is no licence on it - and the CP would come back when the first server comes back online?