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12 Configuring and Deploying the Dell PS Series Multi-Path I/O Device Specific Module with Microsoft Windows | TR1036
Setting
Description
Max sessions per
volume slice
The max number of session connections permitted per volume per member. This
number represents the # of connections a volume will make to each member or
array in the storage pool.
Max sessions per
entire volume
The max number of session connections permitted for a volume. This value must be
greater than or equal to the max sessions per volume slice.
Use MPIO for
snapshots
Optionally include or exclude MPIO for connections to snapshots.
Minimum adapter
speed
Slowest acceptable NIC speed to be used by MPIO
3.1.1 Default Load Balancing policy
When the PS Series MPIO DSM is enabled, the default load balancing policy is Least Queue Depth. When
the MPIO DSM is disabled, the default load balancing policy is Fail Over Only. Generally, it is recommended
to accept the default load balancing policy because it is optimized to run with PS Series SANs.
The three supported options are:
 Fail Over Only: One connection is used for all data until it times out or fails, and then one of the other
available paths is chosen. If this load balancing scheme is selected, the MPIO DSM will not manage
connections to the target.
 Round Robin: Data is sent out to each available connection in a rotating sequence, effectively utilizing
all available ports fully.
 Least Queue Depth: Data is sent out to each available connection, with preference given to the
connection which is least busy at the time the I/O is requested.
Additional unsupported options include Round Robin with Subset, Weighted Paths, and Least Blocks. These
options are not available through the Remote Setup Wizard and will return an error message if they are
selected using the iSCSI Initiator Properties for the target.
3.1.2 Volume session connections
The number of connections per target (volume) depends on the number of arrays in the storage pool and the
number of NICs being used for MPIO. The two controlling settings for target connections are:
 Max sessions per entire volume
 Max sessions per volume slice (pieces of the volume)
By default, the max number of sessions per entire volume is set to 8 and the max number of sessions per
volume slice is set to 2. Refer to Table 1 for descriptions of these settings.
The max number of sessions per slice are based on the number of arrays in the storage pool where the
volume resides. Volume slice refers to the slice (or piece) of the volume on the member storage array. Each