About Proxied Volumes
Proxied Volumes enables many of the SANmelody software advanced services to operate on top of pre-formatted volumes already in use before SANmelody software was introduced into the configuration, without modifying the structure of existing data and with minimal disruption to current operations. Proxied Volumes are most often used as a temporary measure to migrate data from existing storage to a new architecture or to accelerate a deployment to more quickly receive the benefits of SANmelody features. Proxied volumes require a file system of some kind and support all kinds of disk formats, such as Windows, Unix, AIX, and so on.
Some important functions allowed by the Proxied Volumes feature include performance enhancement through caching, replication over IP to any LUN (including non-SANmelody LUNs), risk free deployment without requiring a backup/restore operation, and pass-through access to current disk contents while data is mirrored. A Proxied Volume can be brought into the SAN, served through the storage server, gaining all the capabilities of mirroring, replication, snapshot, etc. without requiring a backup/restore operation.
Proxy Mode is most often used as a temporary measure to migrate data from existing storage to a new architecture or to accelerate a deployment to more quickly receive the benefits of SANmelody features. You should disable Proxy Mode after migrating the data and removing the volume. Whereas a storage server with Proxy Mode disabled automatically discovers and labels new storage, when in Proxy Mode it is necessary to manually identify all newly-discovered storage either as Proxied Volumes or SANmelody-managed standard disks in Disk Manager. Note: After labeling a disk as a standard disk, it can never be used as a proxied volume. Refer to Disk Manager for more information.
SANmelody software treats Proxied Volumes differently from non-proxied virtual volumes:
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SANmelody assumes that the volume is an existing disk that was previously formatted and partitioned by a host.
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SANmelody assumes that the volume includes that host’s file system and live data exists on the volume.
The DataCore Disk Manager snap-in is the interface you will use to configure volumes as Proxied Volumes. You must place the storage server in Proxy Mode in order to configure individual volumes as Proxied Volumes. (See Enabling/Disabling Proxy Mode.) While all logical volumes (non-proxy volumes) managed by SANmelody software are automatically assigned a SANmelody volume label, Proxied Volumes are not automatically tagged with this label. Thus, a storage server running in Proxy Mode can discover these volumes and serve them to an application server without altering the live data on the volumes.
WARNING: It is crucial to enable Proxy Mode on the storage server before attaching the original host volumes to the storage server. If the storage server is not in Proxy Mode, it will discover the original host volumes and write data to the disk, possibly corrupting the file system and/or data. If data is written to the disk, the original partition table would be damaged, rendering the disk unreadable by the host. Thus, when you configure a volume as a Proxied Volume, SANmelody software sees the disk simply as a sequence of disk blocks and does not try to impose its own format on the device.
While SANmelody software supports standard SCSI disk commands (open, read, write, etc.), it does not process proprietary extended SCSI commands for Proxied Volumes.
Proxy mode is not supported for dual path volumes, as these volumes are visible from more than one source.
Related Topics:
Identifying/Creating Proxied Volumes