"vxvm vxdisk error V-5-1-8643 %device%: resize failed" during dynamic LUN expansion

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Article ID: 100022055

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Description

Error Message

vxvm vxdisk error v-5-1-8643 %device%: resize failed

Resolution

A disk that is initialized as sliced will fail when the disk geometry changes as a result of a DLE.
 
Partitions must align with cylinder boundaries. If you dynamically expand a device, and the sector/cylinder value changes from 960 to 1920, this will cause the public region to be overwritten.
 

Example: 
  • Original private region length is 2048 bytes, with a 256 byte offset
  • Target private region length is 2304 bytes

Because the allocation must follow cylinder boundaries, the closest value is 960 * 3 = 2880 for the private region. Then, the expansion geometry changes, and the sector/cylinder value is changed to 1920. It is now necessary to correct the entire label, but we cannot drop to 1920 because this cuts off the private region. So 2 cylinders will give us a length of 3804. This expands into the public region of the disk, causing an overwrite, and producing the error message.


Workarounds:
  • Convert the disk to the CDS (Cross-Platform Data Sharing) format. This eliminates the need to use partition boundaries to set public/private region locations.
  • Adjust the DLE operation so that the disk geometry does not change, and the expansion is done by adding more space to the end of the device.
     
To confirm you are running into this issue, compare the old disk geometry with newly-defined disk geometry using the format command.
 
 

 

Issue/Introduction

A DLE (Dynamic LUN Expansion) fails with error v-5-1-8643.

Additional Information

UMI: V-5-1-8643
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