User`s guide

XStack Storage User’s Guide 83
After you add initiators, you can monitor their status using the Initiator
Access Info screen (refer to Section
6.3.3), Initiator Information screen
(refer to Section
6.4.1), and LUN Map Information screen (refer to Section
6.4.2).
5.3.3 Working with LAGS and VLANS
The XStack Storage unit manages the data ports on the enclosure's back panel using the concept
of LAG ports. In a simple configuration, a LAG port associates a single Ethernet port (i.e., a
physical data port) with a network portal that defines an IP address. The LAG port is the entity
that ties an IP address to a data port. Link Aggregation is a way to combine (or “aggregate”)
multiple data ports in parallel to act as a single logical connection with increased bandwidth, and
the XStack Storage unit can do this, too.
Combining two or more data ports increases the overall bandwidth capability between the XStack
Storage unit and your SAN, and creates resilient and redundant links. These capabilities make the
XStack Storage unit ideal for demanding applications that run in high-performance environments,
such as servers in enterprises, Web servers, and intranet servers gain from the high-bandwidth
capabilities of link aggregation.
The following list summarizes the key benefits of LAGs.
 Improved performance - Combining the capacity of multiple interfaces into one logical link
improves performance because the capacity of an aggregated link is higher than each
individual link alone.
 Intermediate data rates – Link aggregation provides intermediate data rate levels between
the standard network data rates of 10 Mbps, 100 Mbps, and 1000 Mbps, ideal when an
intermediate performance level is more appropriate (such as in environments where a factor
of 10 increase may be overkill).
 Increased availability - If a link within a LAG fails or is replaced, the traffic is not disrupted
and communication is maintained (even though the available bandwidth is reduced).
 Load sharing - Traffic is distributed across multiple links, minimizing the probability that a
single link be overwhelmed.
Figure 5-23 shows an example of a LAG created between the XStack Storage unit
and a Gigabit Ethernet switch. In this example, multiple workgroups are joined to form one high-
speed aggregated link. In this figure, the XStack Storage unit is connected to a Gigabit Ethernet
switch using four 1000 Mbps links. If one link fails between the XStack Storage unit and the
switch, the other links in the LAG take over the traffic and the connection is maintained. This
configuration reduces the number of ports available for connection to external devices.
Aggregation thus implies a trade-off between port usage and additional bandwidth for a given
device pair.