Performance Tuning; Monitoring Performance - Dell PowerVault MD3260 Cli Manual

Performance Tuning

Over time, as a storage array exchanges data between the hosts and physical disks, its performance can degrade.
Monitor the performance of a storage array and make adjustments to the storage array operational settings to improve
performance.

Monitoring Performance

Monitor the performance of a storage array by using the save storageArray performanceStats command.
This command saves performance information to a file that you can review to determine how well the storage array is
running. The following table lists the performance information saved to the file.
Table 13. Storage Array Performance Information
Type of Information
Devices
Total I/Os
Read Percentage
Cache Hit Percentage
Current KB/second
Maximum KB/second
Current IO/second
Maximum IO/second
The general form of the command is:
save storageArray performanceStats file="filename"
file is the name of the file in which you want to save the performance statistics. You can use any file name your
where,
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.
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Description
Devices are:
• RAID Controller Modules— The RAID controller module in slot 0 or 1 and
a list of the virtual disks owned by the RAID controller module
• Virtual Disk— A list of the virtual disk names
• Storage Array Totals— A list of the totals for both RAID controller
modules in an active-active RAID controller module pair, regardless if
one, both, or neither are selected for monitoring
Number of total I/Os performed since the storage array was started
Percentage of total I/Os that are read operations (calculate the write percentage
by subtracting the read percentage from 100 percent)
Percentage of reads that are fulfilled by data from the cache rather than
requiring an actual read from a physical disk
Current transfer rate in kilobytes per second (current means the number of
kilobytes per second since the last time the polling interval elapsed, causing an
update to occur)
Highest data transfer value achieved in the current kilobyte-per-second statistic
block
Current number of I/Os per second (current means the number of I/Os per
second since the last time the polling interval elapsed, causing an update to
occur)
Highest number of I/Os achieved in the current I/O-per-second statistic block