Reclaiming thin storage - example
With InfoScale Operations Manager, you can use the Management Server console to gain visibility into and manage thin-reclamation capable devices.
Thin provisioning is a storage array feature that optimizes storage use by allocating and reclaiming the storage on demand. With thin provisioning, the array allocates storage to applications only when the storage is needed, from a pool of free storage. Thin provisioning solves the problem of under-utilization of available array capacity. Administrators do not have to estimate how much storage an application requires. Instead, thin provisioning lets administrators provision large thin or thin reclaim capable LUNs to a host. When the application writes data, the physical storage is allocated from the free pool on the array to the thin-provisioned LUNs.
The two types of thin provisioned LUNs are thin-capable or thin-reclaim capable. Both types of LUNs provide the capability to allocate storage as needed from the free pool. For example, storage is allocated when a file system creates or changes a file. However, this storage is not released to the free pool when files get deleted. Therefore, thin-provisioned LUNs can become 'thick' over time, as the file system starts to include unused free space where the data was deleted. Thin-reclaim capable LUNs address this problem with the ability to release the once-used storage to the pool of free storage. This operation is called thin storage reclamation.
The thin-reclaim capable LUNs do not perform the reclamation automatically. The administrator can initiate a reclamation manually, or with a scheduled reclamation operation.
The Management Server console provides visibility and management for thin reclamation in the context of the following objects that are discovered by InfoScale Operations Manager:
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Server perspective: Lets you select file systems or disks for a host and perform thin reclamation. The space no longer used is reclaimed from the associated LUNs and made available.
Requirements for reclaiming thin storage
To reclaim thin storage requires managed hosts with a supported Storage Foundation version. Thin reclamation is supported on the following Storage Foundation versions:
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UNIX/Linux: 5.0 MP3, or later
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Windows: 5.1 SP1, or later
In addition, the storage must meet the following requirements:
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The storage must be visible to Storage Foundation as thin reclaimable.
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For UNIX: The LUNs must be a part of a Volume Manager volume which has a mounted VxFS file system.
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For Windows: The LUNs must be a part of a Storage Foundation for Windows dynamic volume which has a mounted NTFS file system.
Reclamation of thin pools requires in addition that the array support the thin-reclamation functionality and that Storage Insight Add-on is configured to discover the enclosure.
Example of reclaiming thin storage
In the following example, a storage administrator reclaims storage from thin pools.
The administrator performs the following procedures to reclaim thin storage.
Note: Although not used in this example, you can also select file systems or disks for a selected host and perform thin reclamation. SeePerforming thin reclamation on file systems or disks.
Identify thin pools for reclamation
You can run the Top Thin Pools for Reclamation report to show the 10 thin pools with the most reclaimable space.
This report has the following requirements:
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InfoScale 8.0 or later
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File System (VxFS) disk layout version 9 or later
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InfoScale Operations Manager managed host (VRTSsfmh) version 7.4.2 or later
You can view this information related to the enclosures for which your user group has at least guest role explicitly assigned or inherited from a parent Organization.
Run thin reclamation on thin pools
You can select one or more thin pools from a selected storage array and either schedule thin reclamation or perform it manually. Thin pools are available if the array supports them and if Storage Insight Add-on is configured for the selected enclosure. Make sure LUNs from these thin pools are consumed by hosts running Storage Foundation.
To perform this task, your user group must be assigned the Admin role on the enclosure. The permission on the enclosure may be explicitly assigned or inherited from a parent Organization.
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