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Chapter 8 Advanced Copy Management
8.2 Functions in the Action Area for Advanced Copy
ETERNUS Web GUI User’s Guide
Copyright 2013 FUJITSU LIMITED P2X0-1090-10ENZ0
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8.2.19 Modify REC Buffer
This function sets parameters of the REC Buffer for copying data via the REC Buffer (in Asynchronous
Consistency mode).
The "Consistency mode" secures the order of data transfer to the remote device for all of the specified REC
sessions. This mode requires constant securement of the dedicated REC Buffer in the cache memory. Copying
via REC Buffer stores multiple REC session I/Os in the REC Buffer for a certain period of time, and copies in
blocks.
The procedure to set the REC Buffer is as follows:
Procedure
1 Select the target REC Buffers to be modified (multiple selections can be made), and click the
[Modify REC Buffer] in [Action].
• Perform REC Buffer settings in both the REC copy source and destination storage systems. Make the REC
Buffer size the same for the storage systems of the copy source and the destination. The size will be
adjusted to whichever is smaller.
• Take REC reverse operation into consideration and specify the same values for the REC Buffers
("Forwarding Interval", "Monitoring Time", "HALT Wait Timer", "I/O Priority Mode", and "Immediate HALT
Mode") in the copy source storage system and the copy destination storage system.
• When changing REC Buffers, suspend the sessions using the target REC Buffers.
• When deleting REC Buffers, stop the sessions using the target REC Buffers.
• When performing bidirectional data transfer, settings for "Send" and "Receive" REC Buffers in the ETERNUS
DX Disk storage system are required.
• The following REC Buffer capacity is secured for the cache memory of each controller:
- ETERNUS DX90 S2: 512MB
- ETERNUS DX410 S2: 4096MB
- ETERNUS DX440 S2: 8192MB
- ETERNUS DX8100 S2/DX8700 S2: 8192MB
• The number of REC Buffers, which can be configured, are as follows:
- ETERNUS DX90 S2: Up to 4
- ETERNUS DX410 S2/DX440 S2: Up to 8
- ETERNUS DX8100 S2/DX8700 S2: Up to 8
• This function cannot be used when the remote device and/or copy path is not set.
• If the usage of the REC Buffer, to which the REC Disk Buffer has already been assigned, is changed to
"Receive" or "Unused", the REC Disk Buffer assignment will be cleared (the REC Disk Buffer itself will not
be deleted).
• Cache memory is not only used for REC Buffers, but also used for the copy table. Note that the REC Buffer
with the maximum size for each model cannot be created depending on the memory capacity in the
ETERNUS DX Disk storage system and cache memory allocation for the copy table.