Solved: RDM multi-writer clustered windows

sandroalvesbras · ‎03-15-2019

Hello,

I configuring a windows 2016 cluster on two VMs in 6.5 compatibility mode, when adding an existing physical RDM on the second node, error appears that the file can not be opened.

I changed the RDM option to multi-writer and managed to add RDM on the second node.

However, I have another Windows 2008 R2 cluster with VMs in 5.5-mode compatibility in the same VMware environment and meet physical rdm disks in non-shared mode and it works normally.

Why did I need to set up multi-writer?

Thank you.

ThompsG · ‎03-16-2019

Hi sandroalvesbrasil,

I guess the issue here is about support. The supported method is to either use physical (across hosts) or virtual (within host) bus sharing and not multi-writer.

For me that would be a statement that you should go with what is recommended as its been tested thoroughly and theoretically is the most stable option. Will the multi-writer option work? Maybe. Will there be issues with data integrity? Maybe. With all these unknowns it is better to stick with what is known especially if you are logging a call for support

Kind regards.

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ThompsG · ‎03-16-2019

Hi sandroalvesbrasil,

You should not need to. Can you confirm that one both VMs that you have a second SCSI controller and that the bus sharing option is set to Physical? Take a look here for more details: https://docs.vmware.com/en/VMware-vSphere/6.0/vsphere-esxi-vcenter-server-601-setup-mscs.pdf

Kind regards.

sandroalvesbras · ‎03-16-2019

It's like None.

I have to put it as Physical, right?

Is that the problem?

But if I keep as configured, is there a problem?

sandroalvesbras · ‎03-16-2019

If I keep with multi-writer do I have performance loss or can I have some data integrity problem?

ThompsG · ‎03-16-2019

Hi sandroalvesbrasil,

I guess the issue here is about support. The supported method is to either use physical (across hosts) or virtual (within host) bus sharing and not multi-writer.

For me that would be a statement that you should go with what is recommended as its been tested thoroughly and theoretically is the most stable option. Will the multi-writer option work? Maybe. Will there be issues with data integrity? Maybe. With all these unknowns it is better to stick with what is known especially if you are logging a call for support

Kind regards.

sandroalvesbras · ‎03-16-2019

Sorry, my questioning was not understood.

I say, if even using SCSI Controller in physical mode and I keep RDM in multi-writer, can I have some problem with data integrity?

I ran a test and it worked after changing the SCSI Controller. That means I would not need to use RDM in multi-writer.

Thank you.

All

RDM multi-writer clustered windows