HP XP P9500 Storage User Manual
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of synchronous operations on performance, or maximize the effectiveness of copy operations to
ensure the best level of backup data integrity. The following options address I/O and performance:
•
RCU options (see
and accompanying information)
•
System- and CU-wide options regarding initial copy (see
“Set number of volumes to be copied
concurrently, path watch time” (page 52)
).
•
Pair options (see field descriptions in
)
Your HP service provider can also help you optimize copy operations and performance as follows:
•
Analyze write-workload. The workload data you collect (MB/s and IOPS) helps determine the
following key elements. When sized properly, they form a data path that operates free of
data bottlenecks under all workload levels. (Bottlenecks severely impact performance.)
◦
Amount of bandwidth
◦
Number of data paths
◦
Number of host-interface paths
◦
Number of ports dedicated for Continuous Access Synchronous Z on the main and remote
system
•
If you are setting up Continuous Access Synchronous Z for disaster recovery, make sure that
remote disk arrays are attached to a host server. This enables both the reporting of sense
information and the transfer of host failover information. If the remote site is unattended by a
host, you should attach the remote disk arrays to a host server at the main site so that the
system administrator can monitor conditions.
The following lists conditions that affect storage system performance and provides recommendations
for addressing them.
Table 12 Conditions affecting performance, recommendations
Recommendation
Description
Condition
Spread write-intensive data across several
volumes to minimize queuing.
Write-intensive workloads, such as database
logging volumes, can have a significant impact
on storage system I/O response times.
Write-intensive
workloads
Spread workloads with large write block sizes
across several volumes.
Workloads with large write block sizes, such
as DB deferred writes, can impact performance.
Large block size
Spread the workload across several storage
systems to use additional channels.
The demand on the main system host channels
can affect performance.
High host channel
demand
Avoid performing restore operations to volumes
that belong to Continuous Access Synchronous
Continuous Access Synchronous Z operations
can have a negative impact on workloads with
Sequential write
operations
Z pairs. Instead, restore data to a scratch
a high percentage of sequential write
volume, and then create the Continuous Access
Synchronous Z pair.
operations, such as batch processing operations
(for example, dump/restore, sort operations).
Consider increasing the cache size of the
Continuous Access Synchronous Z storage
Large cache size improves read performance,
which allows more storage system resources to
Cache size
systems to improve overall performance. For
be devoted to write operations. Insufficient
best results, the cache and NVS capacity of
cache resources results in command retries,
the main and remote system should be the
state-change-pending (SCP) notifications, and
puncture conditions.
same. This allows the remote site to function
adequately during disaster recovery.
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Planning for Continuous Access Synchronous Z