Use this dialog box to view or modify the mount path properties of a disk library.
Properties
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Mount Path
The path where the data is written to and read from.
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Free Space (MB)
The remaining free space on the mount path.
Note
Before you perform a data protection operation, always verify and ensure that sufficient disk space is available on the mount paths that are used by the operation. Data protection operations might be affected if the amount of space on the mount paths is insufficient.
The free space information is, by default, refreshed every 30 minutes. The refresh time can be changed in the Interval (Minutes) between disk space updates option in the Service Configuration tab of the Media Management Configuration dialog box in the Control Panel.
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Size on Disk
The total amount of backup data that is stored in the mount path.
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Capacity (MB)
The total amount of space on the mount path.
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Application Size To Be Pruned
The size of the data on the disk that is eligible for pruning during the data aging process.
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Supports drilling of holes
Indicates whether the mount path supports micro pruning. (Micro pruning is the process of pruning individual data blocks without sealing the corresponding DDB (deduplication database).
Note
Some file systems do not support space reclamation of deleted data blocks (drilling holes) that are not at the end of the file. The lack of support for micro-pruning is usually related to the lack of support for sparse files.
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Description
Use this field to enter a description about the mount path. This description can include information about the mount path's content, any cautionary notes, and so on.
Use unbuffered I/O
Specifies that the MediaAgent will bypass the Microsoft Windows file system buffering by enabling unbuffered I/O. Select this option to increase the speed of operations that access the mount path. This option is only applicable for Windows MediaAgents and disks that are mounted directly (UNC paths are not supported).
Reserve Space for Silo Restore
Select this option if you want to use the mount path to receive Silo stores from Silo restore operations only. When this option is selected, this mount path is not used to store backup data.
Status
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Status
The status of the mount path.
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Enable MountPath
When selected, the mount path is available for all operations from all the MediaAgents accessing or sharing this mount path. Clear this option to disable operations for all the MediaAgents accessing or sharing this mount path.
A mount path's online/offline status reflects its logical availability to the MediaAgent, not its physical availability. For example, a mount path can be enabled even if it is physically unavailable due to a hardware failure.
To disable the mount path for only the write operations and make the data available for read and prune operations, use the Disable mount path for new data in the Allocation Policy tab.
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Offline Reason
Indicates the offline reason, when the Status of the mount path is displayed as Offline.
Device
The following information is displayed for shared static mount paths.
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Device Alias Name
The alias provided by the user, for the device. The alias can be changed at any time without affecting the ability to restore data that may have already been backed up using the library.
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Device Enabled
When selected, the device will be available from all the mount paths that are configured in the device. Clear this option to disable all operations on the device.
Caution
A device can have multiple mount paths configured on the device. Disabling the device will disable all the mount paths and their corresponding MediaAgents from accessing the device.
A device's online/offline status reflects its logical availability to the MediaAgents accessing the device, not its physical availability. For example, a device can be enabled even if it is physically unavailable due to a hardware failure.
Mount Path Properties (Allocation Policy)
Use this dialog box to view or modify the usage properties for the mount path of a disk library.
Mount Path Allocation Policy
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Maximum Allowed Writers
When selected, maximum number of concurrent writers on the mount path will be established.
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Allocate number of Writers
By default, maximum concurrent writers are established on the mount path. To limit the number of writers, type the number of writers that you want to allocate.
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Disable mount path for new data
Specifies that new write operations are not allowed on the mount path. However, read and prune operations can be performed.
Prevent data block references for new backups
When selected, the deduplicated blocks in the mount path will not be referenced when there are multiple mount paths in the library. (Choose this option if you plan to retire the mount path.)
Space Allocation
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Reserve Space (GB)
Specifies the total amount of free space that must be available at all times when the system writes data to the mount path. You can change this value to modify the amount of free space. The minimum allowed reserve space is 2 GB.
For mount paths associated with HyperScale storage pools, the reserve space is set to 4% of the total capacity of the mount path.
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Use until free space on mount path reaches Reserved Space
Specifies that the entire mount path minus the reserve space is used to store valid data.
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Do not consume more than n GB
When this option is selected, the system writes data up to the amount that you specify. However, if that amount is greater than the reserve space allows, the system stops writing data when the reserve space is met, regardless of the amount that you specify for this option.
For example, if you specify 8 GB as the amount for this option, but the space on the mount path is 10 GB and the reserve space is 4 GB, the system stops writing data to the mount path once 6 GB is reached.
Note
The system deducts both the Reserve Space and Do not consume more than n GB values from the FreeSpace, and considers the lesser value after deduction as the Usable Free Space available in the mount path. To view the Usable Free Space in libraries, from the CommCell Browser, expand Storage Resources > Libraries. To view the Usable Free Space in libraries associated with a specific MediaAgent, from the CommCell Browser, expand Storage Resources > MediaAgents > MediaAgent.
Fragmentation
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Minimize fragmentation by allocating write blocks of n MB
This option allows the MediaAgent to preallocate a specified portion of the backup chunk before beginning a write operation. The chunk size should be determined based on the disk array and the file allocation unit size.
Preallocating a specified chunk size before the write operation enables the Operating System to allocate contiguous disk clusters based on the requested chunk size, thus reducing disk fragmentation. This option is supported on Windows MediaAgent. For additional information on determining the chunk size, see CommCell Performance Tuning - Increasing Chunk Size.
Pruning
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Enable Pruning of Aged Data
By default, pruning is enabled. To prevent pruning of aged data, clear the check box.
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Select MediaAgents for pruning aged data based on the associated copy's datapath
By default, pruning request is sent to any MediaAgent that has access to the library, irrespective of whether the MediaAgent is part of the datapath or not.
Select this check box to send the pruning request to only those MediaAgents associated with the datapaths in the Storage Policy copy.