About Dual Path
A Dual Path (DP) configuration allows two storage servers (SDSs) to share the same physical disk. When two SDSs detect the same physical disk, this device is identified as a DP disk.
The diagram below illustrates DP:
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Some special considerations and basic information when using DP disks:
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Additional configuration may be necessary depending on the specific software and operating systems installed on application servers. Refer to our Technical Support Web site for FAQs pertaining to your specific operating system and high availability products.
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Dual path storage is write-through only, meaning it bypasses storage server caching for write operations.
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Virtual volumes created from DP disks or pools will always be multipath mirrors.
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All virtual volumes created from the same DP pool will have the same primary SDS.
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Two independent mirror paths must be defined between SDSs before creating virtual volumes. These paths must be used exclusively for inter-SDS mirrors. Refer to Specifying the Mirror Path.
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Redundant mirror paths are not supported. (If the option is enabled in the Mirror Paths dialog box, redundant paths will only be enabled for non-DP virtual volumes.)
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When using non-DataCore MPIO or AP, configure application servers to use the preferred path to virtual volumes created from DP disks or pools.
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When a snapshot source is created from a DP disk or pool, the destination must be a linear virtual volume.
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Virtual volumes created from DP disks or pools cannot be used as snapshot destinations.
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Proxy mode is not supported for Dual Path volumes.
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Always monitor pool information from the DP pool that has Read/Write Access. The pool that has Read Only Access may not display the latest pool information.
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To change read/write access on DP Pools, see Changing Read/Write Access on DP Pools.