● 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 fol-
lowing characteristics. Check the characteristics of each volume type before selecting the volume type.
Table 33 Characteristics of SnapOPC/SnapOPC+ Operations with Each Type of Copy Destination Logical Volume
Item to compare SDV TPV/FTV
Ease of operation set-
tings
The operation setting is complex because a
dedicated SDV and SDP must be set
The operation setting is easy because a dedicated SDV
and SDP are not required
Usage efficiency of the
pool
The usage efficiency of the pool is higher
because the allocated size of the physical
area is small (8KB)
The usage efficiency of the pool is lower because the al-
located size of the physical area is large with a chunk
size of 21MB / 42MB / 84MB / 168MB
*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 redundantly, 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 be-
tween the copy source data and the copy destination data. EC is suitable for the following usages:
•
Performing a backup
•
Performing system test data replication
•
Prepare an encrypted SDP when an encrypted SDV is used.
•
If the SDP capacity is insufficient, a copy cannot be performed. In order to avoid this situation, an operation
that notifies the operation administrator of event information according to the remaining SDP capacity is
recommended. For more details on event notification, refer to "Event Notification" (page
82).
•
For EC, the data in the copy destination cannot be referenced or updated until the copy session is suspen-
ded. If the monitoring software (ServerView Agents) performs I/O access to the data in the copy destination,
an I/O access error message is output to the server log message and other destinations. To prevent error
messages from being output, consider using other monitoring methods.
1. Function
Backup (Advanced Copy)
89
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays
Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
P3AG-1822-09ENZ0
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