What are the restrictions for meta creation ?

Product :

 

Symmetrix

 

 

Description :

 

What are the restrictions for meta creation ?

 

 

Resolution :

 

Solutions Enabler V7.2 lifts the restriction that required non metadevices to be unmapped while being converted to a concatenated metadevice. A device being converted to a concatenated metadevice can now be mapped and online to the host during the operation. Only unmapped thin devices can be converted to striped metadevices.

 

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Note: A non metadevice being converted to a striped metadevice must still be unmapped before it can be converted.
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Note that RDF devices cannot be used to form metadevices in one step. When this is necessary, the RDF devices must first be converted to non-RDF devices as shown below:

 

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The metadevices must be formed separately on both Symmetrix arrays, and then the metahead on one Symmetrix array can be converted back to an RDF device. Also, once the RDF metadevice has been established, it cannot be modified in one step. If any modifications are required, it will again have to be converted to a non RDF device first.

 

 

The following are restrictions when configuring metadevices:

 

Metamembers cannot be removed from a striped metadevice.

 

To create a striped metadevice, all members must be the same size and have the same mirror protection.

 

To remove a member from a concatenated metadevice, the member must be the tail. You cannot remove inner members.

 

Only the head of a meta may have its type converted.

 

Only the head of a meta is mapped or assigned to the host.

 

All metas must contain at least one metamember. When a meta is formed, at least one member must be added.

 

All metadevices must be composed of devices of the same BCV type (you must convert from RDF devices in order to change metas).

 

Metadevices must be composed of devices that are all of the same FBA emulation type.

 

You must create CKD metadevices using the create dev command, not the form dev command.

 

VDEV metadevices must be composed of virtual devices that are of the same capacity, stripe size, count, and emulation type as the standard devices with which they will be used.

 

An RDF device cannot be used to form a metadevice (refer to the above table) for converting a metadevice for RDF operation. The configuration manager cannot form a metadevice from RDF devices that are RDFA-protected (that is, you cannot convert these devices to non-RDF, form the metadevice, and convert them back to RDF).