HCP System Management Help
Each NFS storage pool contains one or more mount points that are associated with specific NFS storage components. Each NFS storage pool includes all of the storage that’s accessed using the NFS mount points included in the pool.
To enable HCP to access the storage that’s represented by an NFS storage pool, when you create that component, you specify the following information:
•The storage pool name.
•Optionally, a description of the pool.
•Whether you want HCP to compress object data that’s stored on the storage that’s accessed using the NFS mount points in the storage pool.
•Whether you want HCP to encrypt object data that’s stored on the storage that’s accessed using the NFS mount points in the storage pool. If encryption is disabled for the system, this option is not visible.
•For each NFS mount point you want to include in the storage pool:
oThe name of the NFS storage component that represents the physical storage device that’s accessed using the NFS mount point
oThe full pathname of the directory that you want to access using the NFS mount point
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Note: •At any given time, an NFS mount point can be included in only one storage pool. •An NFS storage pool is compliant only if all of the NFS mount points in the pool are associated with compliant NFS storage components. |
When you add an NFS mount point to a new or existing NFS storage pool, HCP creates that mount point and mounts the appropriate storage volume (called an NFS volume or an external storage volume) on a node in the HCP system. HCP then adds that NFS volume to the NFS storage pool.
HCP uses a round-robin algorithm to determine which node to associate with each new NFS volume that’s added to an NFS storage pool. This method of assigning NFS volumes to the nodes in the HCP system ensures that the volumes are distributed evenly among the nodes.
If the node with which an NFS storage volume is associated becomes unavailable, that volume also becomes unavailable. HCP does not reassign the volume to a different node. When the node returns to service, the volume becomes available again.
In the HCP System Management Console, you can use the Hardware and Storage Node pages to view information about the NFS storage volumes (called external storage volumes) that are associated with each node in the HCP system. For information on these pages, see Hardware administration.
Considerations for using NFS volumes
These considerations apply to using NFS volumes with HCP:
•HCP can use multiple NFS shares from a single device that’s represented by an NFS storage component. Keep in mind, however, that the larger the number of shares HCP uses, the greater the I/O load on the device.
•Typically, you specify export options for a share according to the standards for your site. However, if HCP is unable to mount the extended storage volume that you created as an NFS share, you may need to change the export options. After changing the export options, you need to export the NFS share again.
•For each NFS mount point that’s associated with an NFS storage component, you can specify more mount options than the required ones. You might do this, for example, to set the network block size for read or write requests to the optimal size for the storage device that’s represented by the NFS storage component. However, if HCP is unable to mount the extended storage volume that you created as an NFS share, you may need to change the additional mount options that you specified.
•If the share for an NFS volume becomes unavailable (for example, because the extended storage device that’s hosting the share is inaccessible), HCP tries periodically to remount the volume. If, after the share is available again, the remount fails, you can try to manually remount the NFS volume:
1.On the left side of the Storage page, click on Components.
2.In the components list, click on the name of the NFS storage component that’s associated with the NFS volume that you want to remount.
3.At the top of the panel that opens, click on the Mount Points tab.
4.On the Mount Points panel, in the table row that contains the NFS mount point that corresponds to the NFS volume you want to remount, click on the remount control ( ).
HCP attempts to remount the NFS volume. If the remount fails, contact your authorized HCP service provider for help.
To see which node the NFS volume is associated with, mouse over the status icon for the mount point on the Mount Points panel.
•You cannot move an NFS volume from one NFS storage pool to another.
•You cannot control which NFS volume HCP writes data to within an NFS storage pool.
•When HCP creates a mount point for a specific NFS volume, HCP stores a file named .__hcp_uuid__ in the shared directory on the device that’s represented by the NFS storage component associated with that mount point. This file uniquely associates the NFS shared directory with the NFS volume. As a result:
oHCP creates only one NFS storage volume for any given exported share.
oIf you delete an NFS mount point from an NFS storage component, the associated exported share cannot be reused as is. This means that any data remaining in the NFS volume associated with the mount point becomes permanently inaccessible to HCP.
For more information on deleting NFS mount points, see Deleting access points from an extended storage pool.
oTo reuse an exported share after the associated NFS mount point is deleted from HCP, you first need to delete any remaining files from the shared directory, including the .__hcp_uuid__ file.
oIf you inadvertently delete the .__hcp_uuid__ file from an NFS shared directory that contains other HCP data, HCP can no longer use the exported share. Contact your authorized HCP service provider for help in recreating the file.
oWhen you back up an NFS shared directory that’s associated with an NFS volume, you need to ensure that the .__hcp_uuid__ file is included in the backup operation. This ensures that the file still exists in the directory after a restore operation.
•A situation can occur in which HCP can access an exported share but cannot mount the associated NFS volume. In this case, if the .__hcp_uuid__ file is the only file in the shared directory on the extended storage device on which the data in the NFS volume is stored, you can reuse the exported share. To do this:
1.Delete the mount point that’s associated with the NFS volume from the NFS storage component that represents the device on which the NFS volume is stored.
2.Delete the .__hcp_uuid__ file from the shared directory.
3.Create a new NFS mount point for the share on the same NFS storage component from which you deleted the mount point in step 1.
•If an NFS volume becomes inaccessible due to a disk failure on the extended storage device on which the data in the NFS volume is stored, you need to replace the disk, restore the data from backup, and then export the NFS share again.
In this case, the NFS volume needs to be remounted. If HCP doesn’t remount the volume automatically, you can try to manually remount the NFS volume:
1.On the left side of the Storage page, click on Components.
2.In the components list, click on the name of the NFS storage component that’s associated with the NFS volume that you want to remount.
3.At the top of the panel that opens, click on the Mount Points tab.
4.On the Mount Points panel, in the table row that contains the NFS mount point that corresponds to the NFS volume you want to remount, click on the remount control ( ).
If the manual remount fails, try restarting the node with which the NFS volume is associated. To see which node the NFS volume is associated with, mouse over the status icon for the mount point on the Mount Points panel.
•You can restore an NFS shared directory to a different location from where it was originally. If you do this, you need to modify the configuration of the associated NFS mount point to point to the new location. For information on modifying an NFS mount point, see Modifying an extended storage component.
•If HCP cannot create, mount, or use an NFS volume and you’ve already determined that the permissions for the shared directory, the export options for the share, the mount point configuration on the associated NFS storage component in HCP, and the mount options for the mount point are all correct, the problem may exist on the extended storage device that’s represented by the NFS storage component on which you configured the mount point. To resolve such problems:
oEnsure that the NFS share has been exported on the device.
oEnsure that the NFS server is running on the device.
oEnsure that any NFS security software on the device is not blocking access by any of the HCP nodes.
oCheck the system log file on the device for messages indicating device errors. Then correct those errors.
If HCP still cannot create, mount, or use the volume, contact your authorized HCP service provider for help.
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