Database Reference
In-Depth Information
another ESXi host. vSphere Replication is hardware independent, so the target server
can be different from the source server. In addition to being hardware independent,
vSphere Replication is also storage independent. This means you can run your
production virtual machines on a high-performing storage array and replicate your
virtual machines to a remote facility running three-year-old servers with direct attached
disks. vSphere Replication also allows an administrator to select the VMDK file type.
For example, on the production side, the VMDK file type can be Thick Provisioned
Eager Zeroed and on the recovery side the VMDK file type can be Thin Provisioned.
vSphere Replication integrates with Microsoft Windows Volume Shadow Copy Service
(VSS) via VMware tools. Once this has been configured for the virtual machine, writers
are flushed and the application and operating system are quiesced to ensure full
application consistency for backups. If VSS fails for some reason, vSphere Replication
continues despite the failure and will provide OS-consistent backup and generates a
notification that a VSS-level backup was not achieved.
Why is this important for SQL Servers? This provides a hypervisor-level replication of
your SQL Server virtual machines. For some (maybe not all) SQL Servers, the recovery
procedure is “restore from backup.” With vSphere Replication, the ability exists to
replicate this virtual machine to a remote site. A company can buy standalone physical
servers, install ESXi on the direct attached storage, enable vSphere replication, and
now DR exists for all SQL Servers. Finally, for additional cost savings, the VMDK file
format can be changed to Thin Provisioning for increased density and utilization of the
physical assets at the alternate site.
Note
vSphere Replication works against powered-on VMDKs, requires Virtual
Hardware 7 or later, and has an RPO of 15 minutes to 25 hours. For more
information on vSphere Replication, VMware published this white paper:
Overview.pdf
.
vCenter Site Recovery Manager
vCenter Site Recovery Manager (SRM) is a product from VMware that allows for the
automation and orchestration of your disaster recovery plans. SRM automates your
disaster recovery run book. SRM allows for frequent, nondisruptive testing, whether
against the entire run book or a portion of the run book. SRM does require an underlying
replication technology, and it can provide an RPO equal to the underlying replication
technology. SRM provides support for both array-based replication and vSphere
Replication. Need to re-IP your servers at your recover site? SRM can handle this
