redundancy

[bogha]

hi,

what information should i know to do the following:
we will have 2 servers, each one will have a cPanel WHM installed and 2 will have DNS, we want to insure that redundancy is achieved on both servers, means the servers should work as active/standby unit. 2 cPanel active/standby 2 DNS active/standby

also does this have any impact on the mySQL database, do we have to buy another server to use it as the mySQL database or it's possible to sync all the cPanel information from one server to another.

thank you

[cPanelDavidG]

hi,

what information should i know to do the following:
we will have 2 servers, each one will have a cPanel WHM installed and 2 will have DNS, we want to insure that redundancy is achieved on both servers, means the servers should work as active/standby unit. 2 cPanel active/standby 2 DNS active/standby

also does this have any impact on the mySQL database, do we have to buy another server to use it as the mySQL database or it's possible to sync all the cPanel information from one server to another.

thank you

If I understand correctly, you want to have a live cPanel/WHM server, a live remote DNSONLY server and a live remote MySQL server - with standby servers for all 3 in case any of them experience catastrophic failure. Is that correct?

[bogha]

hi,

what i meant is that i will have 4 servers
2 for cPanel/WHM
2 for DNS

i want to know if it's possible to implement active/standby, if a server from cpanel 2 servers is down the other will automatically take its place until the other is restored, the same for DNS which should be handled from WHM servers.

for the MySQL, i think the operation of management MySQL in the linux will be done using the WHM, then i want to know if it's supported to sync the MySQL between the 2 WHM servers or we have to think of other ways, like implementing a sync script between the 2 server.
also last question: WHM can also work as email server or not? do we have to buy another 2 redundant server to implement a SMTP/POP3 or the cPanel/WHM servers can do this operation

thank you.

[cPanelDavidG]

hi,

what i meant is that i will have 4 servers
2 for cPanel/WHM
2 for DNS

i want to know if it's possible to implement active/standby, if a server from cpanel 2 servers is down the other will automatically take its place until the other is restored, the same for DNS which should be handled from WHM servers.

for the MySQL, i think the operation of management MySQL in the linux will be done using the WHM, then i want to know if it's supported to sync the MySQL between the 2 WHM servers or we have to think of other ways, like implementing a sync script between the 2 server.
also last question: WHM can also work as email server or not? do we have to buy another 2 redundant server to implement a SMTP/POP3 or the cPanel/WHM servers can do this operation

thank you.

In such scenarios, it is up to you to implement your own solution for directing traffic to the server that traffic should be directed to. cPanel/WHM itself does not have the capability to direct all its traffic to another server when it experiences catastrophic hardware failure.

Regarding the cPanel/WHM servers, you will need to determine how to synchronize the data between cPanel/WHM servers. You may also want to disable DNS on the cPanel/WHM servers since you intend to use remote DNS servers.

DNS Clustering will handle propagating the DNS records from a cPanel/WHM server to the remote DNS servers. I recommend leaving both DNS servers online at all times so they both have updated records.

With regards to MySQL, cPanel/WHM by default runs MySQL locally. If you want to implement MySQL replication, you will need to consult the documentation for MySQL for how to achieve this. An easier alternative would be to have the primary cPanel/WHM server set up to utilize a single remote MySQL server. If the secondary cPanel/WHM server is a mirror of the primary server, it too can use the same remote MySQL server. However, cPanel/WHM only supports 1 remote MySQL server so if you want multiple MySQL servers, you will need to implement that manually.

Remote mail servers are not natively supported at this time. The ETA for remote mail server support is cPanel version 12.

[Spiral]

what information should i know to do the following:
we will have 2 servers, each one will have a cPanel WHM installed and 2 will have DNS, we want to insure that redundancy is achieved on both servers, means the servers should work as active/standby unit. 2 cPanel active/standby 2 DNS active/standby

also does this have any impact on the mySQL database, do we have to buy another server to use it as the mySQL database or it's possible to sync all the cPanel information from one server to another.

thank you

What you are asking about is true HA/Clustering ....

This is something that is not directly supported by Cpanel but your could could setup an additional server to server as a HA/LB manager to serve as a reverse proxy to direct traffic to mirrored servers though keeping servers synchronized themselves may be a bit of an issue and would definitely need to be 3rd party as Cpanel only supports MySQL and DNS clustering --- not accounts and end user data.

You also MUST do the type of configuration I just said above to do this else you would have to deal with different IP addresses for each server exposed to the outside world and no quick or otherwise seamless way of switching without downtime and that would kind of defeat your point of doing any of that in the first place.

Otherwise, I would probably lean more to getting extra drives and setting up a RAID configuration so in the advent of a drive failure, you can switch over to the other drive(s) and this may be a lot more cost effective and less complicated to maintain than an HA/Cluster scenario and also don't need as many server machines either.

Another option would be to get a cloud server where hardware failures are very unlikely though worst case scenario, you could still in most cases deploy an exact duplicate copy of the server with all it's content usually within a matter of minutes up to an hour and get back online again very rapidly no matter what happens usually.

If you are looking to Cpanel for clustering in and of itself, your only real option is clustering the DNS and setting up your MySQL on a 3rd server that is called from both servers (or clustering the MySQL with manual setup) but synchronizing the account files and data would be completely up to you and will have to come from somewhere outside Cpanel.

The cost overhead of what you want to do though typically doesn't justify itself just to avoid what would usually be very short downtime anyway if any at all except for the most extreme catastrophic of circumstances which is why most would generally opt more for the RAID options.