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June 10th, 2015 19:00

Failover MDM

Hi,

Any idea how to enable the failover MDM ? I saw the mdm_failover binary on MDM server, managed to bring it up but when I did a simulation with secondary MDM goes down, the failover didn't do anything. Can't find the manual either for mdm_failover.


Regards,

7 Posts

June 11th, 2015 05:00

Hi,

Thanks for the reply.

Yes, I meant the mdm_failover explicitly. However, I can't access link that you've given me Not authorized

Regards,

2 Intern

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522 Posts

June 11th, 2015 05:00

Hi,

If the goal is to switch the MDM to the Secondary MDM, you can do this through the CLI:

2015-06-11_8-16-28.png

If you are talking about MDM_failover explicitly, then that is a little more involved given additional standby or tie-breaker MDMs that can be configured and this is a good manual that discusses that scenario:

https://support.emc.com/docu56714_Automatic-MDM-Cluster-Node-Replacement-Technical-Note.pdf?language=en_US

HTH

7 Posts

June 11th, 2015 06:00

Hi,

Already follow you need to be followed back so I can send you private message

2 Intern

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522 Posts

June 11th, 2015 06:00

That might be due to the credentials associated with your account. Send me a direct message offline and I can send it to you.

19 Posts

June 16th, 2015 20:00

dondy, Were you able to get this going? Please post your results and if any future assistance is needed.

7 Posts

June 16th, 2015 20:00

Hi,

Unfortunately No I don't get the documentation that I need yet

19 Posts

June 16th, 2015 21:00

Let me see if we can get this posted on the community.

7 Posts

June 16th, 2015 21:00

Hi,

Finally I can get the documentation and start configuring as stated. However, in all my MDMs server I've already run the script but when I tried to shutdown one of the MDM, the service doesn't seems to run. Not even trying to change the cluster to single mode. It just won't do anything.

Anything that I miss maybe?


Regards,

Dondy

19 Posts

June 17th, 2015 04:00

Since you tried this before specifying the failover MDMs I would suggest deleting the service, see bottom of page 3, and than attempt to rerun the command. Make sure that you are enter the IPs correctly in the CLI too. If you have a single IP per MDM it should look like this.

[mdm1_ip]+[mdm2_ip]

If you have multiple IPs per it should look like

[mdm1_ip1,mdm1_ip2]+[mdm2_ip1,mdm2_ip2]

7 Posts

June 17th, 2015 05:00

[root@scaleio-01 bin]# scli --query_cluster

Mode: Cluster, Cluster State: Degraded, Tie-Breaker State: Connected

Primary MDM IP: 10.211.55.30

Secondary MDM IP: 10.211.55.33

Tie-Breaker IP: 10.211.55.32

Management IP: 10.211.55.30, 10.211.55.33

Name: N/A

[root@scaleio-01 bin]#

State Degraded is because I turn off the secondary MDM to simulate crash.

7 Posts

June 17th, 2015 05:00

Hi,

I did make sure that the previous mdm_failover service are off before I'm putting the new configuration.

Now I can get to the point where the new configuration give me this

Found 3 MDMs' IPs

Found 1 Tie-Breakers' IPs

Successfully started mdm_failover as a service, to stop it use /opt/emc/scaleio/mdm_failover/bin/delete_service.sh

[root@scaleio-04 bin]#

But then again when I simulate to have one MDM (both primary or secondary) goes down, nothing happen.

Any ideas ?

19 Posts

June 17th, 2015 05:00

What is the current cluster state?

scli --query_cluster

19 Posts

June 20th, 2015 07:00

Just got around to testing this out in my lab and it does work for primary and secondary MDMs as well as the TB.

A few things to check:

- Make the MDM software is installed on the one that will be the standby.

- Check to make sure the service is running on all MDMs

# systemctl list-units --type service --all |grep mdm

mdm.service                           loaded active   running scaleio mdm

mdm_failover.service                  loaded active   running scaleio mdm_failover

mdmonitor.service                     loaded inactive dead    Software RAID monitoring and management

Keep us posted on what you find.

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