SRM Limitations to Protect and Recover Virtual Machines
There are few limitations which I will like to highlight
today while protecting and recovering VM with VMware Site Recovery Manager.
1). Protection and Recovery of Virtual Machines in
Suspended State.
When we suspend a virtual machine, vSphere creates and saves
its memory state. When the virtual machine resumes, vSphere restores the saved
memory state so that the virtual machine can continue to operate without any
disruption to the applications and guest operating systems that it is running.
2). Protection and Recovery of Virtual Machines with
Snapshots
Array-based replication supports the protection and recovery
of virtual machines with snapshots, but with limitations. We can specify a
custom location for storing snapshot delta files by setting the workingDir
parameter in VMX files. Site Recovery Manager does not support the use of the
workingDir parameter.
But if you still want to protect the virtual machines with
snapshots than I will recommend going with vSphere Replication but keeping in
mind that you can only recover the latest snapshot. vSphere Replication erases
the snapshot information in the recovered virtual machine. As a consequence,
snapshots are no longer available after recovery, unless you configure vSphere
Replication to retain multiple point-in-time snapshots. For information about
recovering older snapshots by using multiple point-in-time snapshots with
vSphere Replication, see Replicating a Virtual Machine and Enabling Multiple
Point in Time Instances.
3). Protection and Recovery of Virtual Machines with
Memory State Snapshots
When protecting virtual machines with memory state
snapshots, the ESXi hosts at the protection and recovery sites must have
compatible CPUs, as defined in the VMware knowledge base articles vMotion CPU
Compatibility Requirements for Intel Processors and vMotion CPU Compatibility
Requirements for AMD Processors. The hosts must also have the same BIOS
features enabled. If the BIOS configurations of the servers do not match, they
show a compatibility error message even if they are otherwise identical. The
two most common features to check are Non-Execute Memory Protection (NX / XD)
and Virtualization Technology (VT / AMD-V).
4). Protection and Recovery of Linked Clone Virtual
Machines
Array-based replication supports the protection and recovery
of virtual machines that are linked clones if all the nodes in the snapshot
tree are replicated.
5). Protection and Recovery of Virtual Machines with
Reservations, Affinity Rules, or Limits
When Site Recovery Manager recovers a virtual machine to the
recovery site, it does not preserve any reservations, affinity rules, or limits
that you have placed on the virtual machine. Site Recovery Manager does not
preserve reservations, affinity rules, and limits on the recovery site because
the recovery site might have different resource requirements to the protected
site. The only exception is the Reserve all guest memory (All locked) setting,
if it was enabled on the protected VM.
6).Protection and Recovery of Virtual Machines with
Components on Multiple Arrays
Array-based replication in Site Recovery Manager depends on
the concept of an array pair. Site Recovery Manager defines groups of
datastores that it recovers as units. As a consequence, limitations apply to
how you can store the components of virtual machines that you protect using
array-based replication.
Site Recovery Manager does not support storing virtual
machine components on multiple arrays on the protected site that replicate to a
single array on the recovery site.
Site Recovery Manager does not support storing virtual
machine components on multiple arrays on the protected site that replicate to
multiple arrays on the recovery site, if the virtual machine components span
both arrays.
If you replicate virtual machine components from multiple
arrays to a single array or to a span of arrays on the recovery site, the VMX
configurations of the UUID of the datastores on the protected site do not match
the configurations on the recovery site.
The location of the VMX file of a virtual machine determines
which array pair a virtual machine belongs to. A virtual machine cannot belong
to two array pairs, so if it has more than one disk and if one of those disks
is in an array that is not part of the array pair to which the virtual machine
belongs, Site Recovery Manager cannot protect the whole virtual machine. Site
Recovery Manager handles the disk that is not on the same array pair as the
virtual machine as an unreplicated device.
As a consequence, store all the virtual disks, swap files,
RDM devices, and the working directory for the virtual machine on LUNs in the
same array so that Site Recovery Manager can protect all the components of the
virtual machine.
Reference:
SRM DOCS
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