Migration approaches of VM from SAN/NAS to vSAN

Storage vMotion

Storage vMotion is a component of VMware vSphere that allows the live migration of a running virtual machine's (VM) file system from one storage system to another, with no downtime for the VM or service disruption for end users.
  • Feature is included in vSphere Standard and higher editions and vSphere with Operations Management.
  • Existing storage must be accessible by the hosts in the vSAN cluster.
  • No downtime require

Steps for Storage Migration

vSphere replication

VMware vSphere Replication is a hypervisor-based, asynchronous replication solution for vSphere virtual machines. It is fully integrated with VMware vCenter Server and the vSphere Web Client.
  • Feature included vSphere Essentials Plus Kit and higher editions of vSphere and vSphere with Operations Management
  • Host-based replication does not require the vSAN cluster to have access to the existing storage
  • Require Downtime
  • VMware Virtual SAN is a fully supported feature of vSphere 5.5 Update 1 and later.

You can perform as many syncs as you want until the VM is recovered. To minimize downtime you would 1. Perform a delta sync 2. Power down the source VM 3. Perform a final delta sync 4. Recover the VM

Using vSphere Replication adds to the load on the storage. Every virtual machine generates regular read and write operations. Configuring replications on those virtual machines adds another read operation to the regular read and write operations, which increases the I/O latency on the storage. The precise number of virtual machines that you can replicate to Virtual SAN storage by using vSphere Replication depends on your infrastructure. If you notice slower response times when you configure replications for virtual machines in Virtual SAN storage, monitor the I/O latency of the Virtual SAN infrastructure. Potentially, reduce the number of virtual machines that you replicate in the Virtual SAN datastore.
Recover Virtual Machines using vSphere Replication
Performing a recovery with vSphere replication

Sphere Replication using SRM

VMware vSphere Site Recovery Manager (SRM) is a disaster recovery management product that provides automated failover and disaster recovery testing.
VMware SRM speeds disaster recovery time and can prioritize the recovery processes, specifying the order that virtual machines are restarted. VMware SRM automates the process of synchronizing recovery data between the primary and backup data center sites by using a third-part replication product or vSphere Replication to copy virtual machine data to a secondary site. VMware SRM is an add-on product and is not included as part of a vSphere edition. At least one vSphere license is required at both the protected and recovery site.
·       Additional investment for SRM
·       Enable Migration upto 2000 VMs
·       SRM provides the ability to prioritize the order in which VMs are migrated &automatically change IP addresses, if needed.
·       Require Downtime

Using SRM with vSphere replication

Enhance vMotion( Xvmotion)

You can use vMotion to migrate virtual machines to a different host and datastore simultaneously. In addition, unlike Storage vMotion, which requires a single host to have access to both the source and destination datastore, you can migrate virtual machines across storage accessibility boundaries.
In vSphere 5.1 and later, vMotion does not require environments with shared storage. This is useful for performing cross-cluster migrations, when the target cluster machines might not have access to the source cluster's storage. Processes that are working on the virtual machine continue to run during the migration with vMotion.
You can place the virtual machine and all of its disks in a single location or select separate locations for the virtual machine configuration file and each virtual disk. In addition, you can change virtual disks from thick-provisioned to thin-provisioned or from thin-provisioned to thick-provisioned. For virtual compatibility mode RDMs, you can migrate the mapping file or convert from RDM to VMDK.
·       It is included with Essentials Plus and higher
·       It does not require the vSAN cluster to have access to the existing storage
·       vSphere 5.1 and later
·       No Downtime require
 vMotion without shared storage is useful for virtual infrastructure administration tasks similar to vMotion with shared storage or Storage vMotion tasks.
When you move a virtual machine with RDMs and do not convert those RDMs to VMDKs, the destination host must have access to the RDM LUNs. 
Consider the limits for simultaneous migrations when you perform a vMotion migration without shared storage. This type of vMotion counts against the limits for both vMotion and Storage vMotion, so it consumes both a network resource and 16 datastore resources. See Limits on Simultaneous Migrations in the vSphere Web Client.

Cross vCenter vMotion

This capability can be useful for administrators who need to move a workload to a different location but want to retain the properties of the VM.
When the VM moves to another vCenter with VMware Cross vCenter vMotion, the data associated with the VM will follow it such as events and alarms, and properties such as distributed resource scheduler (DRS) and high availability (HA) settings. The VM's universal unique identifier is also preserved during the transition.
·       It is included with Enterprise Plus or vSphere with Operations Management Enterprise Plus
·       It does not require the vSAN cluster to have access to the existing storage
·       vSphere 6.0 and later
·       vCenter Server instances need to be in Enhanced Linked Mode and on the same single sign on domain
Also refer this link Long distance/Cross vCenter vMotion Requirement , when you enable the features or something to consider if your planning on using long distance cross vCenter vMotion

V2V Migration

Virtual to virtual (V2V) is a term that refers to the migration of an operating system (OS), application programs and data from a virtual machine or disk partition to another virtual machine or disk partition. The target can be a single system or multiple systems. To streamline the operation, part or all of the migration can be carried out automatically by means of specialized programs known as migration tools.
·       vSAN filesystem now supported in vmware converter
·       It’s a free downloadable toolf rom the VMware Website 
When migrating these from VMFS to vSAN datastore you should be able to choose which vSAN Storage Policy to apply to each VM/Object so that their components are created to adhere to these policies, so create any specific policies you may require prior to this (or just apply vSAN Datastore Default Policy and change them later).

Migration of RDM based disk

·       migrate a VM to vSAN, any RDM would have to be in virtual mode
·       If the RDM is not Virtual then change the Physical mode to Virtual Mode
·       Virtual RDM (vRDM) can be replicated with vSphere Replication
·       When the VM is recovered with vSphere Replication, the vRDM is recovered as a VMDK.
·       Require Downtime
üApps that can use the VMDK multi-writer option are supported. Example: Oracle RAC
üClustering technologies such as SQL Server AlwaysOn and Exchange DAG that do not require a shared disk are supported.
üClustered apps that require the configuration of SCSI Bus Sharing for VMs (Windows Server Failover Clustering with shared disk) are not natively supported.

Third party Tools like Dell EMC RecoverPoint for VMs or Veeam.
Veeam released support for vSAN in June of 2014. Before that, Veeam customers could, in fact, back up virtual machines (VMs), and more importantly, restore VMs that were hosted on vSAN with no problem, but that support added some important smart logic. This logic means that if you have a Veeam proxy on the same host as a VM, the smart logic will make sure that proxy will do the backup and not a different proxy on a different host. This means a faster backup since there is less network traffic. If a VM was on host A but a proxy on host C did the backup, there is more traffic over the network.

Veeam also supports backing up and restoring the storage policy that is associated with the virtual machine. At restore, the same policy is connected by default, but you can choose a different policy if that is appropriate
Reference link

 






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