Administrator Guide

Live Volume with Linux/UNIX
98 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
In this final demonstration, the replication link is quickly changed from synchronous replication to
asynchronous replication and write I/O requests are applied to the primary Live Volume. Note the reduction in
time required to commit these writes compared to the previous use of synchronous replication.
[tssrv216:/root]# cd /etc; time tar cvf - . | (cd /vol_00; tar xvf -)
[snip]
real 0m18.266s
user 0m0.104s
sys 0m1.328s
10.7.3 Multi-site with LVMR
In this alternate multi-site scenario, the Linux hosts and SC Series arrays are geographically dispersed within
a metro (or multi-state) region. Sites may be connected through MAN or WAN technologies. Additionally, a
third site has been included using the LVMR feature of SC Series storage. Figure 75 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 multi-site use case with LVMR
The third site and data in this scenario is replicated asynchronously. One of its uses may include the remotely
located disaster recovery copy of business-critical data. It should be noted that the LVMR copy is always
associated or paired with the primary SC Series array. If the primary and secondary array roles are swapped,
the LVMR copy automatically transfers and associates or pairs itself with the array that assumes the primary
role. Additionally, this asynchronously replicated copy (unlike a synchronously replicated) is current if the
replication link has sufficient bandwidth and the Replicate Active Snapshot (Replay) feature is enabled, or
current as of the last captured snapshot if the feature is disabled. Consequently, discussions should also be
conducted around acceptable RPO and RTO thresholds and maintaining agreeable SLAs with all business
entities involved.
The technical considerations discussed in the section 10.7.2 should be kept in consideration when setting up
this use case.