Table 31 Characteristics Of Snapopc/Snapopc+ Operations With Each Type Of Copy Destination Logical Volume - Fujitsu ETERNUS DX100 S4 Design Manual

2. Basic Functions
Backup (Advanced Copy)
●
QuickOPC
QuickOPC copies all data as initial copy in the same way as OPC. After all of the data is copied, only
updated data (differential data) is copied. QuickOPC is suitable for the following usages:
• Creating a backup of the data that is updated in small amounts
Performing system test data replication
•
Restoration from a backup
•
●
SnapOPC/SnapOPC+ (*1)
As updates occur in the source data, SnapOPC/SnapOPC+ saves the data prior to change to the
copy destination (SDV/TPV/FTV). The data, prior to changes in the updated area, is saved to an
SDP/TPP/FTRP. Create an SDPV for the SDP when performing SnapOPC/SnapOPC+ by specifying
an SDV as the copy destination.
SnapOPC/SnapOPC+ is suitable for the following usages:
Performing temporary backup for tape backup
•
Performing a backup of the data that is updated in small amounts (generation management is
•
available for SnapOPC+)
SnapOPC/SnapOPC+ operations that use an SDV/TPV/FTV as the copy destination logical volume
•
have the following characteristics. Check the characteristics of each volume type before select-
ing the volume type.
Table 31 Characteristics of SnapOPC/SnapOPC+ Operations with Each Type of Copy Destination
Logical Volume
Item to compare
Ease of operation
settings
Usage efficiency of
the pool
*1: The difference between SnapOPC and SnapOPC+ is that SnapOPC+ manages the history of
updated data as opposed to SnapOPC, which manages updated data for a single generation
only. While SnapOPC manages updated data in units per session thus saving the same data re-
dundantly, SnapOPC+ has updated data as history information which can provide multiple
backups for multiple generations.
●
EC
An EC creates data that is mirrored from the copy source to the copy destination beforehand, and
then suspends the copy and handles each data independently.
When copying is resumed, only updated data in the copy source is copied to the copy destination.
If the copy destination data has been modified, the copy source data is copied again in order to
maintain equivalence between the copy source data and the copy destination data. EC is suitable
for the following usages:
• Performing a backup
• Performing system test data replication
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems Design Guide (Basic)
SDV
The operation setting is complex be-
cause a dedicated SDV and SDP must
be set
The usage efficiency of the pool is
higher because the allocated size of
the physical area is small (8KB)
90
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TPV/FTV
The operation setting is easy because a dedica-
ted SDV and SDP are not required
The usage efficiency of the pool is lower because
the allocated size of the physical area is large
with a chunk size of 21MB / 42MB / 84MB / 168MB
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