Fujitsu ETERNUS DX60 S4 Design Manual page 79

1. Function
Backup (Advanced Copy)
To suspend a Cascade Copy where session 1 is performed before session 2 and session 2 is an EC session,
•
perform the Suspend command after the physical copy for copy session 1 is complete.
A Cascade Copy can be performed when the copy type for copy session 1 is XCOPY or ODX. The copy destina-
•
tion area for XCOPY or ODX and the copy source area for copy session 2 do not have to be completely identi-
cal. For example, a Cascade Copy can be performed when the copy source area for copy session 2 is only
part of the copy destination area for copy session 1.
XCOPY or ODX cannot be set as the copy type for copy session 2 in a Cascade Copy.
For more details on XCOPY and ODX, refer to
•
• To acquire valid backup data in the copy destination for copy session 2, a physical copy must be completed
or suspended in all of the copy sessions that configure the Cascade Copy. Check the copy status for copy
sessions 1 and 2 when using the backup data.
However, if a Cascade Copy performs session 1 before session 2, and copy session 1 is an OPC or QuickOPC
session and copy session 2 is an OPC, QuickOPC, SnapOPC, or SnapOPC+ session, the data in the copy desti-
nation for copy session 2 is available even during a physical copy.
If copy session 1 is an EC session and copy session 2 is an OPC, QuickOPC, SnapOPC, or SnapOPC+ session,
•
setting copy session 2 after setting copy session 1 to an equivalent or suspended state is recommended.
When stopping an OPC or QuickOPC session for copy session 1 during a physical copy, stop copy session 2 in
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advance if copy session 2 is an OPC, QuickOPC, SnapOPC, or SnapOPC+ session.
• If copy session 2 is an EC session, copy session 2 does not transition to an equivalent state until the physical
copy for copy session 1 is complete. For an EC session, a copy session cannot be suspended until the session
transitions to an equivalent state.
If a Cascade Copy performs session 1 before session 2, and copy session 1 is an OPC or QuickOPC session, the
•
logical data in the intermediate volume when copy session 2 is started (the copy destination volume for
copy session 1) is copied to the copy destination volume for copy session 2. A logical data copy is shown
below.
OPC / QuickOPC
: Copy session 1
: Copy session 2
FUJITSU Storage ETERNUS DX60 S4, ETERNUS DX60 S3 Hybrid Storage Systems Design Guide (Basic)
"Server Linkage Functions" (page
OPC / QuickOPC /
SnapOPC /
SnapOPC+ / EC
79
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87).
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