VMware RDM Replication

Hi @Shaokat -

No... Veeam can't replicate RDM. What you can do is install a Veeam Agent in the guest OS & back up the Volume that way. 

If you are using an RDM disk there is no way to replicate it that I am aware of even Veeam will not back it up either.  Unless there is a third-party tool that can do this that is probably the best route to go.

I am pretty sure even VMware SRM does not do this.  I will validate and check but RDM is not an ideal way to add disks to any server and we stay away from them.

Here's the official word from the User Guide & Platform Support 

Mmm...what about CDP replication?  RDM’s can be replicated using snapshot-based replication because you can’t snapshot a RDM.  But CDP is different because it using an IO filter to split the data between the production datastore and the replica target.  I haven’t read anything yet, but I’m going to go check...CDP might work…..

pRDMs are an older way of solving certain problems and have many limitations (such as replicating these with Veeam).

Have you looked into migrating those disks from a pRDM to a vRDM?
https://kb.vmware.com/s/article/2009226

Veeam can handle RDM in virtual mode (vRDM) rather than a RDM in physical mode (pRDM). 

RDMs aren't supported Derek, at least as shown in the link I shared above showing Platform Support, under the Virtual Machines section. 

Based on this RDM in CDP is a no go - System Requirements - User Guide for VMware vSphere (veeam.com)

I think the better thing is using vRDM as noted to get around some of the limitations, but we need to know from the OP how it is configured.

There's a potential option for sure. vRDM. Nice share Tyler. 

Well...RDM is not listed as a source. I think you’re looking at the Veeam agent, but that’s going to be for backups, not replication.  But you could at least backup the data and then use a copy job to copy it to your DR site.  The other thought is if SQL can replicate the data itself to the secondary location….log shipping or sorts as I recall, but it’s been a long time since I’ve done anything with that.

 
https://helpcenter.veeam.com/docs/backup/vsphere/system_requirements.html?ver=120#cdp_source_target

Good thought.  I forgot that there are physical and virtual RDM’s.  Personally, I’m not a huge fan of clustering, either physical or virtual servers.  Seems to add needless complexity in most cases.

"...but that’s going to be for backups, not Replication" - I think it applies to both though. I could be wrong...have been before 😉

hi @Shaokat 
as everybody said before; not possible to do a replication. but veeam agents for windows should do the job for “normal” backups and do a copy after that.

i also like to point out, that there is nearly no reason these days to use RDMs. check shared vdisks for ms failover clustering if needed.

some information:
https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.storage.doc/GUID-710B8E1E-9B33-4229-B974-C51A316C3256.html
https://theitbros.com/share-disk-between-vms-on-vmware-esxi/

if you need more information i can provide some experience.

Best regards
Daniel

From what I’m reading, Clustered Virtual Disks require Fiber Channel and cannot be used with ISCSI….which may be fine for most folks that are trying to cluster disks, but for me, that won’t work because none of my clients are using Fiber Channel.  Another link indicating that FC is required is here:  https://kb.vmware.com/s/article/79616

yes FC is one requirement if i remember correct or vsan will do the job. for me (as also the storage guy) FC is kind of a “nobrainer” sorry about that. not often worked with iscsi sans until now tbh.

No worries.  At my old job, everything was FC, but now that I’m out of Enterprise and dealing exclusively with SMB clients, nobody here has FC.  

what i also like to add is the migration path from rdm or physical san luns to a vmdk (also super easy).

• deploy the veeam agent
• do a backup
• “export” (restore) the disk in question in vmdk format to your vmware datastore
• add the disk to your VM

and done.. of course if you solve the “cluster datastore” problem before.

Daniel

Hi @Shaokat - was what was provided useful to your question? Do you have any further questions? If anything posed did help. it would be very beneficial to mark one of the posts as ‘Best Answer’ so others who come across your post having a similar query can see what was done to achieve the desired result.

Thanks!