Fujitsu ETERNUS DX60 Operation Manual page 103

These copy methods all provide access to the data as it exists at a specific point in time, but there are different features, advantages
and disadvantages to each method as detailed below:
Function Name
Copy method Copy-on-write
method
Timing of actual copy -
load
Effect on access to Yes
the copy source while
copy is running
Effect on access to Yes
the copy source after
copy has "finished"
Lifetime of copy Until session is
session stopped
Size of copy Sufficient for
destination area changed areas
(Snapshot)
Copy action during Copy back only the
restore already copied data
For ETERNUS DX60/
DX60 S2/DX80/DX90,
restore operation is
not available (use OS
tools to copy whole
files instead)
Best used for...
Snapshot Copy
SnapOPC+
Mirror breaking
method
Before "mirror
breaking"
None
None
Until the Equivalent
state is stopped
Same as the copy
source
(Clone)
-
Copy back all the
data by OPC
-
EC
(Suspend
Reverse
Resume)
copies updated
areas
- -
Temporary Backup to disk
backup area for
-
Creation
backup to tape
testing data
-
Backup to disk
for file server and
Copy Type
Clone Copy
EC OPC
Background copy
method
After the copy
command is issued
Minor
Slight during
background copy
Until background
copy is completed
Same as the copy
source
(Clone)
-
If OPC is active,
copy back only
the
Reverse
copied data
->
(Restore OPC)
->
-
only If OPC
completed, copy
back all of the
copied data
-
Backup to disk
-
of Creation
testing data
- 89 -
QuickOPC
Background copy
method
After the copy
command is issued
Minor
Slight during
background copy
Until session is
stopped and copy is
completed
Same as the copy
source
(Clone)
Copy back only the
already copied data
already
is
-
Backup to disk
-
of Creation
testing data
of