The Online Storage view provides reports detailing the current and historical utilization of storage on the Storage Center.
When disk drives are managed by the Storage Center, they are placed within a disk folder, which is simply a logical grouping of physical drives. Disk folders may contain a mixture of drive types, capacities, and speeds. The total capacity of the disk folder is the sum of the capacities of the drives within the folder. Disk folders may also contain disk drives that are specified as hot spares. These hot spare drives are reserved for use as replacement drives in the event another disk in the disk folder fails. Since the space on these hot spares is never used until another drive fails, their capacity is not included in the total capacity for the disk folder.
The Storage Center allocates disk space from a disk folder for volume and replay use as needed based upon the configurations and IO patterns of each volume.
As the Storage Center approaches the end of the disk space available within the disk folder, alerts will be generated warning you of the possibility that you could run out of space.
The first alert generated is a space allocation alert. This alert occurs when no more free disk space is available to be allocated for use by volumes and replays.
The second alert generated is a conservation mode alert. This alert occurs when less than 32 GB of the space allocated for volume and replay use is free. When the Storage Center enters conservation mode, creation of new volumes and replays will be inhibited, and replays will be expired more aggressively.
The final alert generated is an emergency mode alert. This alert occurs when all space allocated for volume and replay use has been exhausted. When the Storage Center enters emergency mode, all volumes associated with this disk folder will be taken offline, and replays will be expired more aggressively. Volumes will not be able to be brought back online until enough disk space is freed to exit this state.
Available Storage Summary
The Available Storage Summary tab contains an overview of storage use for the Storage Center.
Status - This indicates the current status of your storage utilization. When the Total Disk Space Available falls below 20%, the Status value changes to Space Low. When the Total Disk Space Available falls below 5%, the Status value changes to Space Critically Low.
Total disk space - This is the amount of raw disk space available in the disk folder, not counting space on disks designated as hot spares.
Total space allocated for volume use - This is the amount of disk space that has been allocated for use by volumes and replays.
Allocated space used by volumes - This is the amount of disk space actually used by volumes or replays.
Free allocated space - This is the amount of disk space that has been allocated for volume and replay use, but which is not yet used by any volumes or replays.
Unallocated disk space - This is the amount of disk space still available to be allocated for use by volumes and replays.
Disk space saved through compression - This is the amount of disk space that was saved by compressing replays.
Compression ratio - This is the ratio between uncompressed pages and compressed pages.
Total disk space available - This is the total amount of disk space available for use by volumes and replays. This is the sum of the Allocated Space Free and Disk Space Unallocated values.
Space reserved by system - This is the amount of disk space used to store system data such as configuration information and logs.
Unhealthy/Bad disk space - This is the amount of space found on any unhealthy disks, or any bad space found on disks that are still considered healthy. This will only appear if unhealthy or bad disk space has been found.
Space Low Threshold - This yellow bar represents 10% of disk space remaining.
Storage Consumption Trends
The Storage Consumption Trends tab contains reports detailing the history of storage consumption for each disk folder and for each class of disk. It also includes an estimated date at which all space within the disk folder or disk class will be consumed, given past consumption trends.
Data Progression Pressure Reports
The Data Progression Pressure Reports tab contains reports detailing how space is allocated and consumed across the different RAID types, tracks, and storage tiers for each disk folder and type of storage.
A set of tables for each storage tier is shown for each storage type for which a disk folder has been prepared. For instance, if the Assigned disk folder has been prepared for redundant storage with the standard 2MB data page size, there will be a set of tables titled Assigned Redundant 2MB.
Beneath the title for a disk folder and storage type is a summary of data for the disk folder and storage type.
Space available in disk folder indicates the total amount of managed disk space available within the disk folder. This space does not include the capacity for hot spares.
Allocated to Storage Type indicates the amount of disk space that has been reserved for the storage type indicated.
Total space allocated indicates the total amount of disk space from this disk folder reserved for all types of storage. This value may also include a small amount of system overhead.
A table appears for each tier of storage within the disk folder. Above each table is a summary of storage use within that tier.
Space available in tier indicates the total amount of disk space available within the tier. This value does not include hot spares within the tier.
Allocated to Storage Type indicates the total amount of disk space reserved within the tier for the storage type indicated.
Total space allocated indicates the total amount of disk space from this tier reserved for all types of storage. This value may also include a small amount of system overhead.
Each table contains information about how data is distributed amongst RAID types and tracks.
Disk Allocated - This is the amount of raw disk space reserved for the RAID type on the specified tracks of the disks within the storage tier.
Disk Used - This is the amount of raw disk space used by volumes for the RAID type on the specified tracks of the disks within the storage tier.
Pressure Up - This is the amount of space within a given RAID type, Track, and Storage Tier that Data Progression will try to move up to a higher RAID type, track, or storage tier. Note that data is moved only when Data Progression runs, normally once per day, and the speed of data movement is impacted by factors such as the Data Progression Passes to Move and Down/Up Ratio for the volume on which that data resides.
Pressure Down - This is the amount of space within a given RAID type, Track, and Storage Tier that Data Progression will try to move down to a lower RAID type, track, or storage tier. Note that data is moved only when Data Progression runs, normally once per day, and the speed of data movement is impacted by factors such as the Data Progression Passes to Move and Down/Up Ratio for the volume on which that data resides.
Volume Allocated - This is the amount of space reserved for the RAID type on the specified tracks of the disks within the storage tier after RAID is applied.
Volume Used - This is the amount of space used by volumes for the RAID type on the specified tracks of the disks within the storage tier after RAID is applied.
Saved vs RAID 10 - This is the amount of disk space saved by moving data to a RAID type other than RAID 10.
If you have unhealthy disks or bad disks, you may see this value appear.
Unhealthy/Bad disk space - This is the amount of space found on any unhealthy disks, or any bad space found on disks that are still considered healthy.
The Sample Time drop-down box allows you to view historical data samples for this storage type, illustrating how Data Progression is moving data between disk tiers and RAID types.
Volume Distribution Reports
The Volume Distribution Reports tab contains a report detailing how volumes on the Storage Center are consuming space. The report contains information on how the logical space of each volume is consumed, and how this corresponds to physical disk space consumed by that volume.
Server - Volumes are grouped by the server to which they are mapped. Below each server grouping there is a row detailing the totals for all of the volumes mapped to that server.
Volume - This is the name of the volume.
Defined Size - This is the defined logical size of the volume.
Replay Count - This is the number of replays associated with the volume. This count includes the active replay, so any volumes that are up will have a replay count of one, even if no manual or scheduled replays have been taken.
Volume Space Consumed - This and subsequent columns detail the logical volume space consumed by the volume and any associated replays. Also detailed are growth rate trends for both the volume and the associated replays. Finally, the total logical volume space consumed by the volume and all associated replays is displayed.
Disk Space Consumed - This and subsequent columns detail the physical disk space consumed by the volume and all associated replays. If this volume is a view volume that is related to another volume, it may be "borrowing" space from that volume replay branch because the two volumes share some replays. The amount of space borrowed is indicated in the Borrowed column.
Last Updated - The values in this report are not live numbers, but rather are calculated at intervals. The Last Updated column indicates the time at which the values for this volume were last updated.
Many views and wizards in the Compellent System Manager share the following common items.
Storage Management menu: This menu provides access to most Storage Center commands.
View menu: This menu allows you to open different views within the System Manager.
Refresh button: Selecting the Refresh button refreshes the data displayed in all views currently open in the System Manager.
Help menu: This menu provides links to additional information about the Storage Center.
System Time: Indicates the current time on the Storage Center. Clicking on the System Time opens the Time Settings wizard, allowing you to change the time settings for the Storage Center.
Log Off button: Selecting the Log Off button logs you out of the Compellent System Manager.
System Status: The System Status indicator represents the current status of the Storage Center. The indicator will be green, yellow, or red depending upon the severity of alerts currently present on the Storage Center. Select the System Status button to view additional status information in the Alert Monitor view.
Shortcut menu: The shortcut menu bar at the top of the System Manager will be altered based upon the currently selected item. The options presented are specific to the selected item. In many views, these options can also be accessed by right-clicking on the item.
Advisor Pages: Most windows include advisor pages with additional information about the commands and data displayed in the window. To open an advisor page, select the Advisor button.