Fujitsu DX8100 S2 Computer Drive User Manual


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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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5 Click the [Done] button to return to the [REC Buffer] screen.
End of procedure
8.2.21 Create REC Disk Buffer
This function creates an REC Disk Buffer.
When using the REC Consistency mode, REC Buffer shortage may occur due to errors (such as a bad line). Note
that the copy session will be halted if the REC Buffer shortage extends for a certain period of time. The REC
Disk Buffer is used for temporarily saving copy data to avoid these situations.
Requirements for Drive Selection
The requirements for a RAID group that is to be used as an REC Disk Buffer are as follows:
- The number of member drives is four or eight
- Different drive types are not selected at the same time
The following shows the recommended drive configuration of the RAID group:
- Select drives with the same capacity. If drives of different capacities exist in a RAID group, the smallest
becomes the standard, and all other drives are regarded as the same capacity as the smallest drive. In
this case, the remaining drive space will NOT be used.
- Select drives with the same speed. If drives of different speed exist in a RAID group, access performance
of the RAID group may be affected.
- Dividing the mirroring pair drives into different lines (for ETERNUS DX410 S2/DX440 S2)
Registering the license for the Advanced Copy feature is required to create an REC Disk Buffer.
The RAID types, which can be used in REC Disk Buffer, are "High Performance (RAID1+0)" (drive configura-
tion: 2D+2M) and "High Performance (RAID1+0)" (drive configuration: 4D+4M).
When encryption mode is disabled, an encrypted REC Disk Buffer cannot be created by CM.
In the following conditions, REC Disk Buffers cannot be created;
- When Online, SSDs, and SEDs are combined in a single REC Disk Buffer
- When Nearline, SSDs, and SEDs are combined in a single REC Disk Buffer
- When resources for creating an REC Disk Buffer (such as the number of RAID groups and volume num-
bers) are insufficient
(When the maximum number of RAID groups or volumes is already registered in the ETERNUS DX Disk
storage system, a new REC Disk Buffer cannot be created.)
When the REC Disk Buffer creation process is complete, the REC Disk Buffer will be formatted
automatically.
When assigning multiple REC Disk Buffers to an REC Buffer, each REC Buffer has different conditions.
Refer to "8.2.20 Assign REC Disk Buffer" (page 358)
for details.