HP Open View, Руководство по установке и обслуживанию

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IP Mirroring
131 Continuous Access Storage Appliance Installation and Maintenance Guide
IP mirroring performance
In Figure 28 , T0 indicates the time at which the host sends I/O to the local LUN, initiating the
IP mirroring request. T1 indicates the time at which the host receives a completion message
from the local LUN, ending the IP mirroring request. T0 and T1 are measured in milliseconds.
For example, T0 is 10:35:02:15 and T1 is 10:35:03:20. To calculate IP mirroring performance,
subtract T0 from T1.
The time it takes to complete the IP mirroring request on the local and remote LUNs does not
typically change. The time is the same for each request because no other activity affect the
completion of the request locally.
The time it takes to send the request to the remote LUN and for the remote LUN to send a
response to the local LUN is typically changeable and may increase the time between T0 and
T1. The time is different for each request because other factors affect the completion of the
request remotely, such as:
■
Network speed, which is determined by the:
— Quality of the network connection
— Distance between the appliances
■
Other host/LUN activity that requires worker threads
You must establish the correct IP mirroring relationships to ensure that the local and remote
appliances can communicate. Refer to “
Managing IP Mirrors ” in the HP OpenView
Continuous Access Storage Appliance System Administrator’s Guide for more information.