Fujitsu ETERNUS DX100 S4 Design Manual page 101

2. Basic Functions
Backup (Advanced Copy)
To suspend a Cascade Copy where session 1 is performed before session 2 and session 2 is an
•
EC or REC 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 destination area for XCOPY or ODX and the copy source area for copy session 2 do
not have to be completely identical. 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+ ses-
sion, the data in the copy destination for copy session 2 is available even during a physical
copy.
If copy session 1 is an EC or REC 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 sus-
pended state is recommended.
When stopping an OPC or QuickOPC session for copy session 1 during a physical copy, stop
•
copy session 2 in advance if copy session 2 is an OPC, QuickOPC, SnapOPC, or SnapOPC+ ses-
sion.
• If copy session 2 is an EC or REC 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 Quick-
OPC 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 DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems Design Guide (Basic)
"Server Linkage Functions" (page
OPC / QuickOPC /
SnapOPC /
SnapOPC+ /
EC / REC
101
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133).
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