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PERFORM A HOST RESCAN
After the create operation completes the systems administrator must issue a host rescan to allow the host to discover the paths
to the newly created devices. This host rescan is OS specific and also should include a rescan using the host multipathing
software if it must be performed separately from the host rescan, as with PowerPath.
Devices go into a CutoverReady state from a Created state after the host rescan is performed and the target devices are
discoverable. After this is complete, I/O issued by the application will be directed to either the source or the target arrays through
the host multipathing software. This is possible because the target devices are in Passthrough mode. See Appendix A for more
details on the host multipathing software.
CUTOVERREADY AND PASSTHROUGH MODE
Passthrough mode allows the host to write to or read from either the source or target array. Any write that in sent to the target
array will be sent across the SRDF link and serviced by the source array. No data will be kept on the target array while in a
CutoverReady state.
The CutoverReady state is a transitional state. The devices should only be in a CutoverReady state and using pass-through
mode for as long as it takes to check that the Create has succeeded properly, to run the host rescan, and to run the Cutover
operation.
Figure 10.
Figure 10. CutoverReady and Passthrough Mode
Summary of Contents for VMAX
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