Administrator Guide

Live Volume overview
45 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
The autoswap design is meant to make intelligent decisions on the autoswap movement of Live Volume
primary systems while preventing role swap movement from occurring rapidly back and forth between arrays.
Min Amount Before Swap: This attribute is the amount of data accessed from a secondary system. If there
is light, infrequent access to a Live Volume from a secondary array, consider if this makes sense to move the
primary to that system. If so, set this value to a very small value. The criteria for this aspect are defined by the
Min Amount Before Swap attribute for the Live Volume. The value specifies an amount equal to the read/write
access divided by the second-per-sample value. If a sample shows that the secondary array access exceeds
this value, this sample/aspect has been satisfied.
Min Secondary Percent Before Swap: This is the percentage of total access of a Live Volume from the
secondary array on a per-sample basis. The criteria for this aspect are defined by the Min Secondary Percent
for Swap attribute for the Live Volume. If a sample shows the secondary array accessed the Live Volume
more than the defined setting for this aspect, this sample/aspect has been satisfied. The default setting for
this option is 60%. The SC Series array takes samples every 30 seconds and keeps the most recent ten
samples (five minutes total) for analysis. This means that the secondary Live Volume has to have more I/O
than the primary system for six out of ten samples (60%).
Min Time As Primary Before Swap: Each Live Volume has a TimeAsPrimary timer (default setting of 30
minutes) that will prohibit an autoswap from occurring after a role swap has completed. This means that
following a role swap of a Live Volume (either auto or user specified), the SC Series array waits the specified
amount of time before analyzing data for autoswap conditions to be met again. The purpose of this is to
prevent thrashing of autoswap in environments where the primary access point could be dynamic or where a
Live Volume is shared by applications that can be running on servers both at the primary and secondary sites.
Failover Automatically: This indicates whether or not the Live Volume is configured to automatically fail over
and remain available if there is an unplanned outage of the primary Live Volume.
ALUA Optimized: This specifies whether the Live Volume is capable of supporting ALUA Non-Optimized
path reporting. All new Live Volumes created between SC Series arrays running SCOS 7.3 or newer will
automatically be ALUA Optimized. Live Volumes created on SC Series arrays with SCOS 7.2 or earlier can
be updated to be ALUA Optimized once both arrays are running SCOS 7.3 or newer. Live Volumes running
on SCOS 7.2 or earlier will not be ALUA Optimized. Live Volumes which are not ALUA Optimized will report
an Optimal path status for all paths to both the primary and secondary Live Volume.
Report Non-Optimized Paths: This indicates whether or not the Live Volume is configured to report Non-
Optimized paths to the secondary Live Volume (enabled by default). This feature is used in conjunction with
uniform storage presentation and a Round Robin path selection policy where optimal MPIO paths will be
preferred over non-optimal paths for I/O when both types are available. Live Volumes must be ALUA
Optimized and the box must be checked in the Live Volume settings in order to report Non-Optimized paths to
the secondary Live Volume.