Replica vs Copy

[odge]

I couldn't find anything about this on the forum except some certain specific questions which I thought werent appropriate, so I'm starting a new thread.

When is it better to use a copy vs a replica?

We make replica's every night of our VM to a "cheaper than SAN" NAS. Now to get a copy offsite (without using bandwidth) we are going to the datacenter periodically and swapping out a few USB drives. We do replicate critical data at an application level to offsite via bandwidth.

I'm kind of of the mind, let me not use up my primary Datastore IO more than necessary, so I want to replicate to the NAS (last two days for just in case the primary SAN fails, or if I want to quickly revert a single VM to yesterdays copy), and backup to the NAS (for retention reasons).

I also want to avoid snapshoting the machines just to make another copy if I can.

Now, I have a choice, I could copy those replicas daily to the USB using a Veeam copy job, or I could replicate the replicas?

Gostev what do you think? in older versions replicating a replica didn't always work. But replicating a replica, would use less throughoutput each day right? It would be faster, as a VM copy is a full write of all files?

There are other things to think about I'm sure, but they would spin off your fingers faster than from mine.

[Vitaliy S.]

Hi Matthew,

Every job fits well the scenarios this job was designed for. Be aware that VM copy jobs do not track changes, only backup and replication jobs do. Furthermore you cannot specify retention policy for VM Copy jobs.

Now, I have a choice, I could copy those replicas daily to the USB using a Veeam copy job, or I could replicate the replicas?

There are several facts you should keep in mind before proceeding with either of these options. First of all, if you're going to place raw VM files on the NTFS system, then be aware that all your thin disks will be converted to thick disks, as thin disks a VMFS feature only. Secondly, replication jobs cannot use just a USB stick as a replication target, you need to specify ESX(i) host to replicate the VMs to. Given all these facts, I would recommend using backup jobs to create a copy of your replicated VMs. This will allow you to preserve thin provisioned space and save some space on the USB drive by using job compression and deduplication options.

Gostev what do you think? in older versions replicating a replica didn't always work. But replicating a replica, would use less throughoutput each day right? It would be faster, as a VM copy is a full write of all files?

Though I'm not Gostev , I can assure you that you can safely backup/replicate VM replicas. However, please be aware that VMware CBT will not be used for VM replicas, because CBT cannot be enabled on the VM that has already at least one snapshot in its configuration, besides VMware CBT doesn't seem to work (seen a couple of issues reported on these forums) for powered off VMs. The good thing of this approach is that you will NOT stress your production datastore twice and you will always have a good backup copy of the production VM.

Hope this helps!