5 recovery from svol-ssus-takeover – Hitachi TAGMASTORE MK-90RD011-25 User Manual

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Chapter 4 Performing CCI Operations

4.7.5 Recovery from SVOL-SSUS-Takeover

After recovery of the ESCON/FC link, this special state (PVOL_PSUE and SVOL_PSUS) will be
changed to COPY state that original SVOL is swapped as the NEW_PVOL and resynchronizes
(cast off original PVOL) the NEW_SVOL based on the NEW_PVOL by issuing of the
pairresync -swaps command on takeover site (Host B).

Delta COPY

Æ PAIR

P-VOL

Host C

Host A

Host B

PAIR

PSUE

PAIR

SSUS

S-VOL

Host C

Host A

Host B

COPY

pairresync -swaps

on Host B only

S-VOL

P-VOL

Host C

Host A

Host B

PAIR

S-VOL

P-VOL

If the pairresync -swaps command has been failed at the ESCON/FC link is not restored, then
this special state (PVOL_PSUE and SVOL_PSUS) is NOT changed.

Failback after recovery on Host B. After recovery with execution of the pairresync -swaps
command on Host B, if you stop the applications on Host B and restart the applications on
Host A, then horctakeover will execute Swap-Takeover, even though Host A cannot
communicate with remote Host B.

Host C

Host A

Host B

PAIR

horctakeover

on HostA

S-VOL

P-VOL

Host C

Host A

Host B

PAIR

P-VOL

S-VOL