Fujitsu ETERNUS DX60 S3 User Manual page 812

Appendix A Parameter List
A.3 Volume Management
• Sequential Parallel Multi I/O Count (SPMC)
Description
Input condition/
Display contents
• Extreme Cache Pool
Description
Input condition/
Display contents
•
The ETERNUS DX60 S3 and the ETERNUS DX200F do not support the EXCP. In this case, "Extreme Cache Pool" and
"Current Extreme Cache Pool" are not displayed.
•
When selecting volumes that cannot use this parameter as the target of this function, this item is not selected
and cannot be specified.
•
The EXCP setting for the following volumes are fixed to "Disable" and cannot be changed.
-
Volumes (Standard type volumes, Standard (LUN Concatenation) type volumes, and WSVs) that are created
in a RAID group configured with SSDs or SSD SEDs
-
Volumes (TPVs) that are created in a TPP configured with SSDs or SSD SEDs
-
ODX Buffer volumes
Specify the value of the Sequential Parallel Multi I/O Count.
It is not necessary to change the default value for normal use. If multiple volumes with
different settings are selected and [Modify Cache Parameters] is clicked, the field is
blank.
For asynchronous I/O (I/O is issued at once regardless of the order), the I/O process in the
CM may be switched and discontinuity may occur. SPMC is used to determine the
sequential data access (Read I/O and Write I/O) by using the start address for the
previous I/O and the start addresses for specified number of I/Os before and after the
previous I/O. Compared with "SS" and "SDS" which determines the sequential access by
LBA numbers, SPMC can be used for large I/Os.
A larger SPMC may cause random access to be determined as sequential access,
resulting in reduced performance due to incorrect prefetching. Also, SPMC is not
expected to have an effect on data access with multiple I/O sizes.
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Select whether to "Enable" or "Disable" the EXCP.
It is not necessary to change the default setting for normal use.
If multiple volumes are selected when starting this function and different EXCP settings
have been specified for each volume, "Enable" is selected for this item. This item is
displayed when EXCP is enabled for the ETERNUS DX.
•
Enable
•
Disable
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ETERNUS Web GUI User's Guide (Settings)
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