Plesk Slave Server

[tompken]

Hi, Community!

I was wondering if there is a way to set up a backup ("slave") server for Plesk (running 9.5 + ASL@Centos5 atm). I would like it to be hosted in a separate country and keep a mirror of all the main functions like websites, databases and emails.

The way I see it, the slave server periodically mirrors the content (hopefully in a smart incremental way) of the main server and - if the main server goes down - it takes over the job of serving the content.

Then there is a matter of merging the new stuff it produced (emails, db changes) with the "master" once it comes back up. Well, DBs are smart enough to handle it (at least mysql is). Emails can be simply sent over. Files can be locked for changes when in "emergency" mode. So it looks like something very possible to achieve.

Anyone heard of a solution? Googling for plesk backup / slave only finds me stuff about backing up plesk and slave dns...

[BruceLee]

There are different approaches to achieve something like this.
Syncing of contents might be a first step. But it's not a failover at all.
The traffic (DNS) would have to be routed to the destination for example in case of an outage.
A lot of things to take care of. You can do a lot with scripting and opensource binary.

You could take a look at Plesk Expand. Maybe it fits you needs:
http://www.parallels.com/download/expand23/

[Choji]

Hello,

I'm also interested in using a second Plesk to be used as a backup server for when the primary server goes down.

However, the second server we have doesn't have a Plesk license.
Currently, it is being used to just copy mysql databases and some automatic file backups by rsync. It doesn't work so well with mail backups.
Is it really necessary for me to have one, even if it's just going to be a backup?

Choji

[faris]

Parallel's inflexible lisencing system makes this difficult. The default key (for 10.x onward) allows full functionality for 14 days. Then it stops. So you could shut down Plesk on the backup server, and just synch everything. Except you can't. You need to keep that installation up to date. So every now and then you need to run the updater. Which will run Plesk, which probably won't work, so you can't do it. Bah!

But look-- this is not the right way of doing things IMHO. It won't work well. At the very least you'd need DNS to be elsewhere in order to change IPs quickly. If you just change nameserver host records you can be waiting 48 hours and it is totally out of your control.

You would be better off with either a daily full system backup, a CDP solution or a virtualised environment. Virtualisation allows you to clone or backup an entire machine easily. This backup or clone can be kept on a second hardware node. If the first goes down, you fire up the backup on the other hardware node. Unfortunately you still get hit by lisencing (e.g. our HNs allow 10 containers per node. If one goes down I need one node to run 20 containers. Not going to happen unless I get a temporary 20 node licence, which will take time. So we have 2 hours hardware replacement on all our nodes, so if one does down we'll be back up within 4-6 hours realistically, including restoring all container data from the backup server.

Better still, wait for Parallels Cloud Server 6. As long as you have a minimum of three hardware nodes, the failure of any one of them will not be noticed, as each chunk of data is replicated more than once between nodes. Sort of like RAID5 but for entire servers! Other virtualisation technologies can do something slimilar, but mostly require an external SAN which itself could go down.

[Choji]

Virtualization of a secondary physical server is something I've also been considering. I will look into more of this, but from what you're saying, I see that the license is still an issue.

Many thanks!

[faris]

There are non-commecial options, like OpenVZ which, at the end of the day, is Virtuozzo but without the GUI-based admin and backup stuff. There is also proxmox and other options. All worth looking into.

[Choji]

Ok, so here's my plan:

Format and install an OS on my secondary server (probably CentOS 5..

Install say, VirtualBox and create a virtual environment.

Set up Webmin with qmail, spamdyke, spamassassin and whatever else that's been used on the master server so that the slave mimics most of its functionality.

Then I need to change the DNS records so that there's another MX record pointing to mail2.domain at a lower priority.

Then I need to set up some form of relaying system on the secondary server, including the filtering with Spamdyke, Spamassassin etc
I'm not quite sure how this is done - reading up on it, it's probably to do with adding a record on rcpthosts, perhaps?

Does this sound at all feasible or have I got the wrong end of the stick?

P.S. Should I be opening a new thread? I know it's a related topic but it has been a couple of months since it was started and I didn't start it to begin with.

[Choji]

Anyone have any opinions on my idea?

You would be better off with either a daily full system backup, a CDP solution or a virtualised environment. Virtualisation allows you to clone or backup an entire machine easily. This backup or clone can be kept on a second hardware node. If the first goes down, you fire up the backup on the other hardware node. Unfortunately you still get hit by lisencing (e.g. our HNs allow 10 containers per node. If one goes down I need one node to run 20 containers. Not going to happen unless I get a temporary 20 node licence, which will take time. So we have 2 hours hardware replacement on all our nodes, so if one does down we'll be back up within 4-6 hours realistically, including restoring all container data from the backup server.

I've decided to look for a way without using Plesk seeing the license issue seems to be in my way.
I'm just a little unsure about the way to virtualize. In what way is it beneficial other than having more addresses to point at in the MX record?