Do VMs on host Server need physical connectivity to external shared storage (iSCSI)

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Hi everyone.
In my lab setup I am using 4 Servers (S1, S2, S3 & S4) and external shared storage (hpe MSA 2040). Now I made S1 as my self-hosted engine and S2 is HA for my RHV-Manager running on S1. Remaining two servers (S3 and S4) are my additional hosts adding to S1 for spawning VMs.

Now my query is:
-> Do I need to connect (Physically) S3 and S4 servers to my shared storage? If 'yes' why?
-> If I spawn VMs on S3 and S4, where do these VM configuration data stored?

Thanks

Responses

You will need a data storage domain (on the MSA 2040) to accommodate the templates and disks of the VM's. The admin portal on the hosted engine supports the following storage types: NFS, POSIX compliant FS, GlusterFS, iSCSI and Fibre Channel. The need for physical connection depends upon the selected storage type.

What do you mean with VM configuration data? The RHV meta data of VM's is stored in the local postgres database running inside the hosted engine. The configuration of the VM itself is on it's disk (on the data storage domain).

We are using iSCSI storage connection between Servers and MSA 2040. We created a data storage domain on MSA 2040 to accommodate VM's data from all the servers. Do we still need physical connection between Servers (S3 & S4) and MSA 2040?

Note that RHV-Manager won't be running on S3 and S4.

Thanks

According to: http://searchstorage.techtarget.com/definition/iSCSI
iSCSI, which stands for Internet Small Computer System Interface, works on top of the Transport Control Protocol (TCP) and allows the SCSI command to be sent end-to-end over local-area networks (LANs)

S3 and S4 need a TCP connection to the MSA2040 (using their existing networking). Go to the admin portal of the hosted engine and add hosts S3 and S4. This will configure your hosts and a wrong configuration will be result in a failed addition and give you a clue about what is missing.

Hi Siem, Thanks for your reply.

My direct question is "Do I need to connect (Physically) S3 and S4 servers to my shared storage? If 'yes' why?"

I attached my lab setup image above. Please reply!!!

Thanks

Yes, you need a connection between the MSA2040 and S3/S4. The hosts use this connection to access the data storage domain containing the templates and disks of the VM's.

When the MSA2040 and S3/S4 are in the same network, you should be fine and adding the hosts via the admin portal should establish the logical connection with the MSA 2040.

Hi Siem,

When the MSA2040 and S3/S4 are in the same network, you should be fine and adding the hosts via the admin portal should establish the logical connection with the MSA 2040.

Since all our servers (i.e. s1, s2, s3 & s4) and MSA2040 are planned to be in the same network and our RHV-M run only on s1 & s2, shall we consider that there is no need of physical connection b/n MSA2040 & s3/s4, please confirm. Thanks in advance.

When all servers and the MSA2040 are in the same network, there is no need for an extra, physical connection.

Hi Siem, Small correction in my statement. All my Servers (S1, S2, S3, S4) are connected to switch and reachable each other. But my MSA connected directly to S1 (where RHV-Manager is running) and S2 (Manager HA)., Other two servers S3 & S4 are not connected to MSA.

Updated my original diagram. Please have a look.

-> If I add my S3 and S4 servers to RHV-Manager (S1), will S3 & S4 access MSA (shared storage) through S1 or not?

Thanks in Advance!!!

You configure the NFS- or iSCSI-path of a storage domain in the RHV-manager and that merely stores a string in the RHV database, it does not access the storage domain itself. When you add a hypervisor, the RHV-manager transfers this path to the hypervisor and the hypervisor itself will access the path.

When S1 and S2 use a separate network to access the MSA and this network is not accessible by S3 and S4, they will not be able to access the MSA.

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