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Chapter 5 Volume Management
5.2 Functions in the Action Area for Volume
ETERNUS Web GUI User’s Guide
Copyright 2013 FUJITSU LIMITED P2X0-1090-10ENZ0
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5.2.17 Permit Advanced Copy
This function releases the protected volumes.
Released volumes can be used as the copy destination volume.
The procedure to release a volume protection is as follows:
Procedure
1 Select the protected volume to be released (multiple selections can be made) and click
[Permit Advanced Copy] in [Action].
→ A confirmation screen appears.
2 Click the [OK] button.
→ Releasing copy destination protect starts.
3 Click the [Done] button to return to the [Volume] screen.
End of procedure
5.2.18 Modify Cache Parameters
This function changes the cache parameters of each volume.
Performance of the storage system varies depending on the cache hit ratio. The ETERNUS DX Disk storage
system detects sequentiality when a host requests Read/Write. If sequentiality is detected when a Read
request is issued, the cache hit ratio is improved by reading the sequential data into the cache memory in
advance. The characteristics of Read/Write requests from the host depends on the system. Performance of the
storage system may improve by specifying a cache parameter that is suitable for the system that is being
used.
The following parameters can be specified:
• Cache Page Capacity
Specify the cache capacity that is used by volumes.
• Prefetch Limit (PL)
Specify the value to calculate the amount of data that is to be read from the drive in advance (amount of
data to prefetch from the disk) when the cache detects the sequentiality of data access (Read IO).
• Force Prefetch Mode (FP)
Specify whether to perform prefetch even if the sequentiality of data access (Read IO) is not detected.