HP 3PAR Operating System Software - Manual (Page 100)

Optimizing Synchronization Speed over Distances
As the physical distance increases between the systems in the Remote Copy pair, latency can
increase and throughput can decrease for both RCIP and RCFC configurations.
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To optimize the speed and size of data transfers between a Remote Copy pair, enter:
# setrcopytarget tunelinks <bandwidth> <latency> <target_name>
◦ <bandwidth> - Bandwidth of the connection to the target system in KB/s
◦ <latency> - Round-trip latency of the connection to the target system in milliseconds
◦ <target_name> - Name of the target system
Additional Resource: “About the Remote Copy Commands” (page 222)
Troubleshooting RCIP Autonegotiation Issues
By default, HP 3PAR Storage Systems use autonegotiation for the RCIP GigE interfaces.
However, autonegotiation does not always function correctly, which results in different duplex or
speed configurations for the system’s GigE port and the local switch port. This discrepancy causes
a significant impact to performance, and it can prevent the Remote Copy links from coming up.
To correct an autonegotiation problem:
1.
Set the local switch port to full duplex, if possible.
To change the switch port settings, refer to your switch manufacturer’s documentation.
2. Set the storage system port duplex and speed setting.
# controlport rcip speed <value> full <N:S:P>
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<value> - Network speed.
◦ If you are able to change the local switch port, specify the maximum supported speed
of your network (HP recommends a value of 1000).
◦ If you are using unmanaged switches or are unable to change the local switch port
settings, set the system GigE ports to match the local switch port settings.
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full - Specifies “full duplex”
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<N:S:P> - Location of the GigE port you are setting, expressed as node:slot:port
Additional Information:
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“About the Remote Copy Commands” (page 222)
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HP 3PAR InForm OS Command Line Interface Reference
Considering Additional Impacts on Performance
Volume Group Mode
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Asynchronous periodic mode: Snapshots are usually created in asynchronous periodic mode,
which can add latency because copying old data to the snapshot space can impact write
performance.
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Synchronous mode: In synchronous mode, host writes have to be sent to the backup system,
and an acknowledgement must be sent back to the primary system, before the host is
acknowledged. This process adds latency to host writes, especially for RCIP configurations.
100 Optimizing Performance