Appendix A Parameter ListA.3 Volume ManagementETERNUS Web GUI User’s Guide (Settings)Copyright 2015 FUJITSU LIMITED P2X0-1270-13ENZ0812• Sequential Parallel Multi I/O Count (SPMC)• Extreme Cache PoolDescription 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 withdifferent settings are selected and [Modify Cache Parameters] is clicked, the field isblank.For asynchronous I/O (I/O is issued at once regardless of the order), the I/O process in theCM may be switched and discontinuity may occur. SPMC is used to determine thesequential data access (Read I/O and Write I/O) by using the start address for theprevious I/O and the start addresses for specified number of I/Os before and after theprevious I/O. Compared with "SS" and "SDS" which determines the sequential access byLBA 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 notexpected to have an effect on data access with multiple I/O sizes.Input condition/Display contents0 - 32Description 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 settingshave been specified for each volume, "Enable" is selected for this item. This item isdisplayed when EXCP is enabled for the ETERNUS DX.Input condition/Display contents • Enable• Disable• 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 selectedand 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 createdin 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
