http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm Consistency group in Hitachi USPV Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm Hello!   Could you please give me an explaination of what is Consistency group (CTG) in Hitachi and how exactly it works?   Thanks....... :-)     Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm#11 http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm A consistency group guarantees in order delivery of packets from devices within each group.  This allows the remote disk subsystem to apply deltas in order when packets arrive in a different order than they were sent.  Does that answer your question? Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm#12 http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm Thanks Snig.........   just wanting to know in bit more detail, what is it exactly that helps maintaining this consistency and how????   Thanks & regards....... Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm#13 http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm In the mainframe world HDS uses time stamps to keep track of packets in flight and applies them in order on the remote side. In the open systems world HDS uses simple markers to do the same thing.  Since there is no central clock on al Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm#14 http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm Thanks for your reply Snig :-) Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm#15 http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm No problem buddy.  Now let's get some more discussion going here... Mon, 9 Mar 2009 11:14:02 GMT http://www.rupturedmonkey.com/orca/topic/Consistency-group-in-Hitachi-USPV.htm#16