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On Tue, Oct 16, 2018 at 4:35 PM Mahesh Falmari <Mahesh.Falmari@veritas.com> wrote:

Hi Nir,

We have few queries with respect to RHV which we would like to understand from you.

1. Does RHV maintains the virtual machine configuration file in back end?

Just like we have configuration files for other hypervisors like for VMware it is .vmx and for Hyper-V, it is .vmcx which captures most of the virtual machine configuration information in that. On the similar lines, does RHV also maintains such file? If not, what is the other way to get all the virtual machine configuration information from a single API?

There is a OVF storage, but this is not meant for consumption.

Please follow the first section in:

https://ovirt.org/develop/release-management/features/storage/backup-restore-disk-snapshots/

This explains how to use the API to get a OVF for a VM.

2. Is VM UUID the only way to uniquely identify virtual machine in the RHV infrastructure?

What we understand is that VM UUID is the way to identify virtual machine uniquely in the RHV infrastructure. Would like to know any other way than this?

UUID is the way to do this.

3. Do we have any version associated with the virtual machine?

Just like we have hardware version in case of VMware and virtual machine version in case of Hyper-V, does RHV also associate any such version with virtual machine?

The HW version is based on the VM machine type.

4. Is it possible to create virtual machines with QCOW2 as base disks instead of RAW?

We would like to understand if there are any use cases customers prefer creating virtual machines from QCOW2 as base disks instead of RAW ones.

That is a possibility in cases of thin disk on file storage.

5. RHV Deployment

What kind of deployments you have come across in the field? Does customers scale their infrastructure by adding more datacenters/clusters/nodes or they add more RHV managers? What scenarios trigger having more than one RHV manager?

We are all kind with oVirt. I depends on the use case.

6. Image transfer

We are trying to download disk chunks using multiple threads to improve performance of reading data from RHV. Downloading 2 disk chunks simultaneously via threads should take approximately the same time. But from our observations this takes roughly 1.5 times.
Can RHVM server requests in parallel, if so are there any settings that need to be tweaked?

Here is an example:
Request 1 for chunk 1 from thread 1, Range: bytes=0-1023
Request 2 for chunk 2 from thread 2, Range: bytes=1024-2047
Takes roughly 1.5 seconds, whereas a single request would take 1 second. Expecting it to take just around 1 second.

7. Free and Thaw operation

For cinder based VM, API recommended for FS consistent backup.

POST /api/vms/<ID>/freezefilesystems
POST /api/vms/<ID>/thawfilesystems

Why do we need this whereas it is not required for other storage?

Creating a snapshot does this for you in a case where you have the oVirt guest agent install on the guest.

Thanks & Regards,
Mahesh Falmari