Re: Question on HA configuration.
- Date: Wed, 30 May 2018 07:17:10 -0400
- From: Dan Ritter <dsr@xxxxxxxxxxxxxxxx>
- Subject: Re: Question on HA configuration.
On Wed, May 30, 2018 at 02:01:05PM +0500, Muhammad Yousuf Khan wrote:
> Dear Sir,
> As you have mentioned earlier below.
> wtprd0X (search for ‘wtprd0’) - these are front end web server nodes for an
> HA cluster (uses HAProxy in pfSense)
> wtsqlprd01-3 (search for wtsql) - these are 3 MySQL servers for the backend
> of a site in HA
> I can understand the purpose of 3 frontends but how 3 Mysqls are designed
> are they replicating to each other get updated or or is this a enterprise
> Cluster in a sense where you are running multple nodes of MYSQL but
> application sees only one and if any of the instance goes down the other
> stands for backup. is it like.
> how does the 3 MYsql stack works. ?
There's lots of information here:
The basic options for databases are:
- single write master, multiple read-only replicas
- single write which is also single read, with a standby replica
that can be substituted in case of a disaster
- multiple read/write replicas available simultaneously, but
performance is often slower because they all need to
coordinate potential conflicts
- multiple read/write replicas with "sharding", so conflicts are
- and then there are combinations of the above.
The information you have given is insufficient to tell which
scenario is happening.