- Notes, cautions, and warnings
- Getting started
- New user setup
- Configure and provision a new storage system
- Using the PowerVault Manager interface
- System concepts
- About virtual and linear storage
- About disk groups
- About RAID levels
- About ADAPT
- About SSDs
- About SSD read cache
- About spares
- About pools
- About volumes and volume groups
- About volume cache options
- About thin provisioning
- About automated tiered storage
- About initiators, hosts, and host groups
- About volume mapping
- About operating with a single controller
- About snapshots
- About copying volumes
- About reconstruction
- About quick rebuild
- About performance statistics
- About firmware updates
- About managed logs
- About SupportAssist
- About CloudIQ
- About configuring DNS settings
- About replicating virtual volumes
- About the Full Disk Encryption feature
- About data protection with a single controller
- Working in the Home topic
- Guided setup
- Provisioning disk groups and pools
- Attaching hosts and volumes in the Host Setup wizard
- Overall system status
- Configuring system settings
- Managing scheduled tasks
- Working in the System topic
- Viewing system components
- Systems Settings panel
- Resetting host ports
- Rescanning disk channels
- Clearing disk metadata
- Updating firmware
- Changing FDE settings
- Configuring advanced settings
- Changing disk settings
- Changing system cache settings
- Configuring partner firmware update
- Configuring system utilities
- Using maintenance mode
- Restarting or shutting down controllers
- Working in the Hosts topic
- Working in the Pools topic
- Working in the Volumes topic
- Viewing volumes
- Creating a virtual volume
- Creating a linear volume
- Modifying a volume
- Copying a volume or snapshot
- Abort a volume copy
- Adding volumes to a volume group
- Removing volumes from a volume group
- Renaming a volume group
- Remove volume groups
- Rolling back a virtual volume
- Deleting volumes and snapshots
- Creating snapshots
- Resetting a snapshot
- Creating a replication set from the Volumes topic
- Initiating or scheduling a replication from the Volumes topic
- Manage replication schedules from the Volumes topic
- Working in the Mappings topic
- Working in the Replications topic
- About replicating virtual volumes in the Replications topic
- Replication prerequisites
- Replication process
- Creating a virtual pool for replication
- Setting up snapshot space management in the context of replication
- Replication and empty allocated pages
- Disaster recovery
- Accessing the data while keeping the replication set intact
- Accessing the data from the backup system as if it were the primary system
- Disaster recovery procedures
- Viewing replications
- Querying a peer connection
- Creating a peer connection
- Modifying a peer connection
- Deleting a peer connection
- Creating a replication set from the Replications topic
- Modifying a replication set
- Deleting a replication set
- Initiating or scheduling a replication from the Replications topic
- Stopping a replication
- Suspending a replication
- Resuming a replication
- Manage replication schedules from the Replications topic
- About replicating virtual volumes in the Replications topic
- Working in the Performance topic
- Working in the banner and footer
- Banner and footer overview
- Viewing system information
- Viewing certificate information
- Viewing connection information
- Viewing system date and time information
- Viewing user information
- Viewing health information
- Viewing event information
- Viewing capacity information
- Viewing host information
- Viewing tier information
- Viewing recent system activity
- Other management interfaces
- SNMP reference
- Using FTP and SFTP
- Using SMI-S
- Using SLP
- Administering a log-collection system
- Best practices
- System configuration limits
- Glossary of terms
Dell PowerVault ME4 Series Storage System Administrator’s Guide
About performance statistics
You can view current or historical performance statistics for components of the storage system.
Current performance statistics for disks, disk groups, pools, tiers, host ports, controllers, and volumes are displayed in tabular format. Current statistics show the current performance and are sampled immediately upon request.
Historical performance statistics for disks, pools, and tiers are displayed in graphs for ease of analysis. Historical statistics focus on disk workload. You can view historical statistics to determine whether I/O is balanced across pools and to identify disks that are experiencing errors or are performing poorly.
The system samples historical statistics for disks every quarter hour and retains these samples for 6 months. It samples statistics for pools and tiers every 5 minutes and retains this data for one week but does not persist it across failover or power cycling. By default, the graphs show the latest 100 data samples, but you can specify either a time range of samples to display or a count of samples to display. The graphs can show a maximum of 100 samples.
If you specify a time range of samples to display, the system determines whether the number of samples in the time range exceeds the number of samples that can be displayed (100), requiring aggregation. To determine this, the system divides the number of samples in the specified time range by 100, giving a quotient and a remainder. If the quotient is 1, the 100 newest samples will be displayed. If the quotient exceeds 1, each quotient number of newest samples will be aggregated into one sample for display. The remainder is the number of oldest samples that will be excluded from display.
- Example 1: A 1-hour range includes 4 samples. 4 is less than 100 so all 4 samples are displayed.
- Example 2: A 30-hour range includes 120 samples. 120 divided by 100 gives a quotient of 1 and a remainder of 20. Therefore, the newest 100 samples will be displayed and the oldest 20 samples will be excluded.
- Example 3: A 60-hour range includes 240 samples. 240 divided by 100 gives a quotient of 2 and a remainder of 40. Therefore, each two newest samples will be aggregated into one sample for display and the oldest 40 samples will be excluded.
If aggregation is required, the system calculates values for the aggregated samples. For a count statistic (total data transferred, data read, data written, total I/Os, number of reads, number of writes), the samples' values are added to produce the value of the aggregated sample. For a rate statistic - total data throughput, read throughput, write throughput, total IOPS, read IOPS, write IOPS - the samples' values are added and then are divided by their combined interval. The base unit for data throughput is bytes per second.
- Example 1: Two samples' number-of-reads values must be aggregated into one sample. If the value for sample 1 is 1060 and the value for sample 2 is 2000 then the value of the aggregated sample is 3060.
- Example 2: Continuing from example 1, each sample's interval is 900 seconds so their combined interval is 1800 seconds. Their aggregate read-IOPs value is their aggregate number of reads (3060) divided by their combined interval (1800 seconds), which is 1.7.
You can export historical performance statistics in CSV format to a file on the network for import into a spreadsheet or other application. You can also reset current or historical statistics, which clears the retained data and continues to gather new samples.
For more information about performance statistics, see Viewing performance statistics, Updating historical statistics, Exporting historical performance statistics, and Resetting performance statistics.
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