Dell PowerVault MD3000i Command Line Interface Guide - Page 97

The general form of the command is: save storageArray performanceStats file="filename" where file is the name of the file in which you want to save the performance statistics. You can use any file name your operating system can support. The default file type is .csv. The performance information is saved as a comma-delimited file. Before using the save storageArray performanceStats command, run the set session performanceMonitorInterval and set session performanceMonitorIterations commands to specify how often statistics are collected. Changing RAID Levels When creating a disk group, define the RAID level for the virtual disks in that group. You can later change the RAID level to improve performance or provide more secure protection for your data. To change the RAID level, run the following command: set diskGroup [diskGroupNumber] raidLevel=(0|1|5) where diskGroupNumber is the number of the disk group for which to change the RAID level. Changing Segment Size When creating a new virtual disk, define the segment size for that virtual disk. You can later change the segment size to optimize performance. In a multi-user database or file system storage environment, set your segment size to minimize the number of physical disks needed to satisfy an I/O request. Use larger values for the segment size. Using a single physical disk for a single request leaves other disks available to simultaneously service other requests. If the virtual disk is in a single-user large I/O environment, performance is maximized when a single I/O request is serviced with a single data stripe; use smaller values for the segment size. To change the segment size, run the following command: set virtualDisk ([virtualDiskName] | ) segmentSize=segmentSizeValue Maintaining a Storage Array 97