Performing thin provisioning reclamation on dynamic volumes and disks allocated from a Fujitsu ETERNUS storage array can cause concurrent application I/O to the volume to fail with write protection errors.

Article:TECH164853  |  Created: 2011-07-18  |  Updated: 2012-03-23  |  Article URL http://www.symantec.com/docs/TECH164853
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Article Type
Technical Solution

Product(s)


Issue



Performing thin provisioning reclamation on dynamic volumes and disks allocated from a Fujitsu ETERNUS storage array can cause concurrent application I/O to the volume to fail with write protection errors.


Environment



This problem is applicable for the following Fujitsu ETERNUS arrays:

  • ETERNUS DX400 S2 series (firmware less than V10L20)
  • ETERNUS DX80 S2/DX90 S2 (firmware less than V10L20)
  • ETERNUS ETERNUS DX400 series
  • ETERNUS DX8000 series
  • ETERNUS4000 series
  • ETERNUS8000 series

 


Cause



Physical storage reclaimed from an ETERNUS LUN is not immediately available to be reallocated. While it is not available, the storage is still considered provisioned to the LUN from which it was reclaimed. Since a LUN cannot be provisioned with more physical storage than the logical size of the LUN, a LUN that has just been reclaimed has a reduced amount of free physical storage that can be allocated to it. Application writes may fail during and for a short while following a Reclaim operation because they require more physical storage to be allocated than the reduced free pool can supply.


Solution



Fujitsu recommends stopping application I/O before starting thin provisioning Reclaim operations on storage from ETERNUS storage arrays, and waiting for awhile after reclamation is complete before restarting I/O.




Article URL http://www.symantec.com/docs/TECH164853


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