Administrator Guide

Synchronous replication use cases
27 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
infrastructure (this includes network, fabric, and storage) can scale to support the amount of data being
replicated and the rate of change.
4.5.1 Hyper-V and VMware
As discussed in previous sections, replicating the file objects that form the construct of a virtual machine takes
advantage of the intrinsic encapsulation and portability attributes of a VM. Along with hardware
independence, these attributes essentially mean the VM can be moved to any location where a supported
hypervisor exists, and a VM or group of VMs are quickly and easily registered and powered on depending on
the hypervisor and the automation tools used to perform the cutover. Compare this to legacy methods of
disaster recovery in which physical or virtual servers are built from the ground up at the recovery site,
applications needed to be installed and configured, and then large amounts of data needed to be restored
from tape. Instead, at the time a disaster is declared, virtual machines and their configured applications are
essentially ready to be added to the hypervisor’s inventory and powered on. Virtualization and replication
shave off massive amounts of recovery time, which helps achieve targeted RTO. When the VMs are powered
on, their application data payload from the most recently completed replication is already present, meeting the
RPO component of the DR plan.
Virtualization and replication combined meet aggressive RTOs and RPOs
4.5.2 Microsoft SQL Server and Oracle Database/Oracle RAC
Aside from infrastructure servers such as Microsoft Active Directory
®
, LDAP, DNS, WINS, and DHCP,
database servers are among the first assets to be recovered. Typically, databases are classified as tier 1
infrastructure (tier 1 assets included in a DR plan receive first recovery priority) and database servers are the
first tier that must be brought online in a multi-tier application architecture. The next online is the application
tier servers, and then the application front end (on either client desktops or a load-balanced web portal).
RTO is a paramount metric to meet in testing and executing a live business continuation plan. In a DR plan,
all steps are predefined and executed in order according to the plan; some steps may be carried out in
parallel. Successfully recovered database servers are a required dependency beginning early in the DR plan.
This includes bringing up application and web servers that have a critical tie to the database server. The more
databases a shared database server hosts, the broader the impact because the number of dependent
application and front-end tiers fan out.
Industry analysis reflects data growing at alarming rates across many verticals. Providing performance and
capacity is not a challenge with current technology, but protecting the data is. Data growth drives changes in
technology and strategy so that SLAs, RTOs, and RPOs can still be maintained even though they were
defined when data was a fraction of the size it is today. Restoring 10 TB of data from tape is probably not