Hitachi G200 - Page 70

• In the following figure, the TC P-VOL also functions as a SI P-VOL. This
configuration allows you to use SI for on-site data backup in case of TC
failure. Or, the TC S-VOL can be used to provide remote backup of the SI
P-VOL in case of a SI failure.
Figure 4-1 Shared TC P-VOL with SI P-VOL
In this configuration, you can only delete TC pairs when the SI P-VOL
status is RCPY. The following table shows possibilities of TC pair
operations according to the SI P-VOL status.
SI P-VOL
status
TC pair operations
Create Split Resync Delete
Switch operations
between the primary
and secondary sites
(horctakeover)
COPY(PD)/
COPY
COPY(SP)/
COPY
COPY(RS)/
COPY
Yes Yes Yes Yes Yes
PAIR Yes Yes Yes Yes Yes
PSUS(SP)/
PSUS
Yes Yes Yes Yes Yes
PSUS
PSUE
Yes Yes Yes Yes Yes
COPY(RS-
R)/RCPY
No No No Yes No
• In the following figure, the TC S-VOL also functions as a SI P-VOL. In this
configuration, SI provides another (or several more) backup copies of a
TC P-VOL.
When a SI P-VOL is shared with the TC S-VOL, the write operation to the
TC P-VOL takes a longer time than normal. This is especially true when
the SI pair is in the PSUS(SP)/PSUS status and is caused by the SI
copying process.
4-8
Sharing TrueCopy volumes
Hitachi TrueCopy® User Guide for Hitachi Virtual Storage Platform Gx00 and Fx00 Models