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From:Mat Keep Date:March 7 2013 1:37pm
Subject:Re: Active/Passive MYSQLSQL Cluster, setup using Pacemaker with Corosync
and DRBD.please share some more points here.
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Hi Ravi
MySQL Cluster is a different and separate product from the clustering 
approaches, such as DRBD with Pacemaker, implemented to protect a 
regular MySQL server

MySQL Cluster uses the NDB storage engine to automatically shard, 
distribute and replicate your database across a cluster of nodes over a 
network.  You can learn more about MySQL Cluster here:
http://www.mysql.com/products/cluster/

MySQL with the InnoDB storage engine is often deployed with DRBD and 
Pacemaker / Corosync to provide lossless failover. It is a stack that is 
supported by Oracle as part of the MySQL Enterprise Edition offering.  
The whitepaper posted as follows provides details on how to configure 
(note, registration required):
http://www.mysql.com/why-mysql/white-papers/mysql-high-availability-drbd-configuration-deployment-guide/

I can put you in touch with one of our consultants if you wish to 
discuss DRBD further

On 07/03/2013 11:56, Ravi Kiran PENTYALA wrote:
> Hi All,
>
>
> Article  on  Active/Passive  MYSQLSQL Cluster, setup  using Pacemaker with
> Corosync and DRBD
>
> Introduction:
>
> We use two nodes, one active (that answers requests from apps) and the
> other on passive mode. If the active server is down, the passive one will
> automatically take its position (being the active node).
> One issue that must be remembered is that we use DRBD to replicate the
> data between the nodes, then we need to have a disk or partition exclusive
> to DRBD, which should be mounted to  mysql directory  /data01 , from our
> cluster setup 'Rancho' servers db701a is  in active mode &701b is in
> passive mode(standby)
>
> root@db701a:~# mount
> /dev/drbd0 on /data01 type ext4 (rw)
>
> root@db701b:~# mount
> /dev/sda1 on /boot type ext4 (rw)
>
>
>
> If there is an failover in the active mode(i.e db701a) ,will automatically
> switches to db701b .then passive server will be active , sync will be from
> b to a.
> Important note :We need to  leave one partition exclusive to DRBD, on
> active node of the server .
>
> Overview of MySQL with Clustering Application:
>
> DRDB (Distributed Replication Block Device)  is one of the leading
> solution for Mysql when combined with Pacemaker , Corosync. DRBD
> synchronizes data at the block device (typically a spinning or solid state
> disk) – transparent to the application, database and even the file system.
> Any changes made on the active host are synchronously replicated to the
> standby host by DRBD, they are accessible for reads and writes on exactly
> the same on both the nodes , the two hosts (Active/Standby) are required in
> order to provide physical redundancy; for suppose if we are using virtual
> environments those 2 hosts should be on different physical machines, one
> important feature no shared storage is required at any point of time , the
> services will be active on one host and in standby mode on the other.
> Pacemaker and Corosync combine to provide the clustering layer that  sits
> between the services & Hosts
> Pacemaker is responsible for starting and stopping services, ensuring that
> they are running on exactly one host at time.
> Corosync provides the  messaging infrastructure between the nodes that
> enables Pacemaker to do its job,
>
> it also handles the nodes ,  within the cluster and informs Pacemaker for
> any changes required  in case of failovers.
> ·         Building of HighAvailability clusters from commodity hardware,
> without the requirement for shared-storage.
> ·         Automatic failover and recovery for service continuity.
> ·         An end-to-end, integrated stack .
> ·          synchronous replication, to ensure failover between nodes
> without the risk of losing committed transactions
>
> Three important things to be noted
> ·         drdb should be mounted to active node
> ·         Making sure  mysql data directory , & my.cnf files are pointed
> to  specified location.
>
> root@db701a:~# ls -l /etc/mysql/my.cnf
> lrwxrwxrwx 1 root root 20 Mar  6 10:54 /etc/mysql/my.cnf ->
> /data01/mysql/my.cnf
> root@db701a:~# ls -l /var/lib/mysql
> lrwxrwxrwx 1 mysql root 13 Mar  3 16:47 /var/lib/mysql -> /data01/mysql
>
> ·         Virtual IP should be pointed to active node first .
>
>
> Please share your some more points .
>

-- 
Regards

Mat Keep
MySQL Product Marketing & Management
Oracle Corp.
+44 (0)7765 898-605





Thread
Active/Passive MYSQLSQL Cluster, setup using Pacemaker with Corosyncand DRBD.please share some more points here.Ravi Kiran PENTYALA7 Mar
  • Re: Active/Passive MYSQLSQL Cluster, setup using Pacemaker with Corosyncand DRBD.please share some more points here.Mat Keep7 Mar