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22 BP1038| Best Practices and Guidelines for Integrating the Dell EqualLogic FS7600 and FS7610 into an Existing SAN
The size of the NAS Reserve space that is allocated determines the number of volumes that are created for
each controller pair. A minimum of two volumes will be created for each NAS appliance. The maximum
volume size supported by the EqualLogic arrays is 15 TB; therefore if the space allocated to the NAS
Reserve is greater than 30 TB, an additional pair of volumes will be created. This process continues until
the capacity requirement is satisfied.
Volumes that are allocated to the FS Series NAS Appliance are controlled by the appliance, so many
operations that are available in Group Manager and CLI access for traditional block volumes are disabled
for the volumes that makeup a NAS Reserve. This includes options such as Auto-replication, snapshots,
and the ability to online/offline a volume. Instead, snapshot and replication functionality is available
through NAS-specific commands in Group Manager or the CLI. This functionality enables system
administrators to implement file system aware snapshots and replication.
Once the NAS cluster is configured, Group Manager can be used to monitor statistics such as free and
used capacity of pools, NAS Reserve, NAS file systems (containers), Snapshot reserve, and used snapshot
space.
8.5 Monitoring an existing SAN
SAN HQ is included with every EqualLogic storage system and is ideal for monitoring EqualLogic SANs.
Administrators can collect data from the SAN and review it to ensure that there is sufficient storage and
I/O capacity for current needs as well as future growth. Figure 7 shows an example of the SAN HQ user
interface and some of the many statistics that it can provide.
Prior to adding an FS Series NAS Appliance to an existing SAN, Dell recommends using SAN HQ to collect
statistics about the existing SAN. Administrators should carefully monitor historical disk capacity usage and
trends to ensure that there will be sufficient free pool space to integrate the FS Series NAS Appliance.
Administrators should examine performance statistics such as the average IOPs over longer periods of
time as well as examining any short bursts of activity. Understanding which hosts each type of activity
comes from helps the administrator determine optimal configuration for pools, number of arrays needed,
and other settings.
Administrators should also look at statistics such as Queue Depth to help understand the average amount
of outstanding I/O that is waiting for service. Higher numbers indicate higher workloads from attached
hosts and in some cases may indicate the need for additional disk I/O capacity (more physical disk
spindles) to satisfy performance needs. Latency is also an important factor that affects the response time
of applications. Higher latencies may be an indicator of slower response times for the attached hosts and
applications running on them. However it is also important to note that larger I/O request or block sizes
will usually result in longer latencies than smaller block sizes. Activities such as backup and restore or
replication, which usually involve very large block sizes, may show higher latencies but this typical and
acceptable for most environments.