Home VMware What is SCSI reservation?
What is SCSI reservation? PDF Print E-mail
Written by Siva   
Wednesday, 03 November 2010 04:56

When multiple hosts access the same shared storage; this SCSI reservations occurs.

SCSI reservations LOCK the LUN or LUNs the VMFS resides upon. It does not lock the partition on a LUN but the entire LUN. SCSI reservations are locks that happen on the SAN/NAS device serving up the LUN.

Because of this the only way to elliminate a SCSI reservations is to balance your VMFS activities across multiple independent VMFS. So:

  • VMFS covering multiple LUNS causes all the LUNs to effectively LOCK but really it is only the one holding the metadata. Effectively because no metadata update can occur until the lock is cleared.

 

  • VMFS covering one LUN causes a lock of the LUN.



If a VM spans more than one VMFS, then an action that causes a metadata update for that VM locks ALL LUNS.

 

 
 

Advertisement

Featured Links:
HREmail.com
Looking for job? Try HREmail.com
Want to have CMS based Websites?
Try siliconwebcreators.com to CMS based websites.
VM Solutions Inc
For best VM solutions..
Digital Procedure Inc.
Looking for Oracle /SAP /Weblogic Consulting services? visit digitalprocedure.com