Administrator Guide

Live Volume with Linux/UNIX
96 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
10.7.2 Multi-site
In this multi-site scenario, the Linux hosts and SC Series arrays are geographically dispersed within a
metropolitan (or multi-state) region; sites may be connected with MAN or WAN technologies. Figure 74
depicts this scenario. It should be noted that this scenario can also be scaled down and applied towards
single-site deployments as well.
Live Volume in a multi-site use case
The Live Volumes are synchronously (in either HA or HC modes) replicated across SC Series arrays. In this
scenario, the alternate array volumes are mapped to a secondary Linux host instead. It should be noted that
the volumes mapped to the secondary Linux host are not shared volumes and do not possess shared I/O
management and locking mechanisms. These secondary volumes would need to be remounted to reflect any
data changes that were written to the primary volumes. For this reason, the integrity of data across both
primary and secondary volumes is guaranteed (in either HA or HC modes) as long as the replication link is in
a known good state.
The secondary Linux host can be used in various ways including, but not limited to, the following use cases:
• These volumes can be used to present a consistent read-only copy of this data to a remotely located
site; this can apply not only for data distribution reasons, but to also manage and minimize any data
access latency concerns.
• The consistency of these volumes (and the integrity of the data that it guarantees) also lends itself
towards database replication use. Databases (and applications) can be brought online at the
remotely-located site, in either read-only mode or used in a disaster recovery after the roles of the SC
Series arrays are swapped (the secondary array becomes the primary array).
• These volumes can also be used to complement virtualization technologies such as Red Hat
Enterprise Virtualization (RHEV) to allow for the replication of virtual machine workgroups from one
site or hypervisor to another site or hypervisor. RHEV hosts its virtual machines on a storage domain
that in turn is correlated through a one-to-many relationship to one or multiple backing SC Series
volumes. These volumes are enabled with Live Volume or are synchronously replicated to an
alternate site or secondary array. At the alternate site, these storage volumes can then be used to