Document LVM striped volume type deprecation

[WebberHuang1118]

Summary

• identify dm-thin as the supported LVM CSI volume type for GA
• deprecate striped volumes and document their snapshot, clone, restore, and capacity limitations
• add migration guidance for existing pre-GA striped volumes
• update the LVM StorageProfile example to use dm-thin

Related Issue

harvester/harvester#11334

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[jillian-maroket]

Review done

[jillian-maroket]

Suggested change

The **striped** volume type was available before the LVM CSI driver reached general availability, but is deprecated and is not included in the GA support scope. Striped logical volumes allocate their full capacity when they are created. Snapshots, clones, and restores also require full data copies, which consume additional capacity and I/O and can cause timeouts. Retrying an interrupted copy can also make it difficult to determine whether the operation completed successfully.

The **striped** volume type, which was available prior to the LVM CSI driver reaching general availability (GA), is deprecated and excluded from the GA support scope. Unlike thin-provisioned volumes, striped logical volumes allocate their full capacity upon creation. Operations such as snapshots, clones, and restores require full data copies, consuming additional storage capacity and I/O while increasing the risk of timeouts. Furthermore, retrying an interrupted copy operation can obscure whether the process completed successfully.

[jillian-maroket]

Suggested change

	Before upgrading to a version that removes striped-volume support, migrate data from existing striped volumes:
	1. Create a dm-thin volume group and StorageClass. A volume group can contain only one local volume type, so use a different volume group from the existing striped configuration.
	1. Stop or quiesce the workload to prevent changes while its data is copied.
	1. Create replacement volumes with the dm-thin StorageClass, and migrate the data using the workload's supported backup, restore, or copy procedure.
	1. Update the workload to use the replacement volumes and verify the data before removing the striped volumes and StorageClass.
	Before upgrading to a Harvester version that removes support for this volume type, migrate data from existing striped volumes:
	1. Create a new dm-thin volume group and StorageClass (separate from the existing striped configuration).
	1. Stop or quiesce the workload to prevent data changes during the migration process.
	1. Create replacement volumes using the new dm-thin StorageClass, then migrate the data using the workload's supported backup, restore, or copy procedure.
	1. Update the workload to use the replacement volumes and verify data integrity before deleting the original striped volumes and StorageClass.

[jillian-maroket]

Suggested change

	For LVM storage, use a dm-thin StorageClass. The striped volume type is deprecated and is outside the LVM CSI GA support scope. For more information, see [dm-thin and Striped Volume Types](./addons/lvm-local-storage.md#dm-thin-and-striped-volume-types).
	You must use a dm-thin StorageClass for LVM storage. The striped volume type is deprecated and excluded from the LVM CSI general availability (GA) support scope. For more information, see [dm-thin and Striped Volume Types](./addons/lvm-local-storage.md#dm-thin-and-striped-volume-types).

[WebberHuang1118]

We can only merge this update after the LVM CSI Driver reaches GA.