Every symmetrix director has 4 processors, Every processor has 2 ports namely (0/1 or C/D). drives are connected to these ports via fiber cables.  So for eg director 1 processor A, we have 2 ports namely 1A C port and 1A D port. the drives are connected to these ports using FC-AL technology, basically fiber channel loops, all drives are in a loop like a token ring network. thats is why ports are also called loops.Each drive carries an ALPA (Arbitrated Loop Physical address)value something simillar to wwn's.  ALso every port is controlled by 2 directors, the dual initiator, or the Rule 17 logic. So for director 1 the dual initiator is dir 16 (coz 1+16=17, called rule 17) so 1A  loops will also be controlled by 16A. But the 16A paths remain inactive, they will only become active if dir 1A fails. [IMAGE] Now Each DAE(Disk Array enclosure )in Symm has 15 drives configured. So as said above following rule 17. each DAE will associate with dirs either (1with 16 or 2 with 15 or 6 with 11 and 5 with 12) Lets take an example of a DAE where C loop is configured on director 1 and 16.. So the drives are configured in such a way as eg: 01a will have drive C0 then 16a will C1, then 01a again takes drive C2 and 16a takes C3.. so it contnues..  [IMAGE]
E:\Program Files\EMC\SYMCLI\bin>symdev list -noport |more Symmetrix ID:          Device Name           Directors                  Device--------------------------- ------------- -------------------------------------                                                                           CapSym  Physical               SA    DA :IT  Config        Attribute    Sts   (MB)--------------------------- ------------- ------------------------------------- 0053 Not Visible            ???:? 01A:D19 2-Way Mir     N/Grp'd      RW       30054 Not Visible            ???:? 16B:C18 2-Way Mir     N/Grp'd      RW       30055 Not Visible            ???:? 16A:D18 2-Way Mir     N/Grp'd      RW       30056 Not Visible            ???:? 01B:C15 2-Way Mir     N/Grp'd      RW       30073 Not Visible            ???:? 01A:D9  2-Way Mir     N/Grp'd      RW       30074 Not Visible            ???:? 16B:CC  2-Way Mir     N/Grp'd      RW       30075 Not Visible            ???:? 16A:DC  2-Way Mir     N/Grp'd      RW       30076 Not Visible            ???:? 01B:CD  2-Way Mir     N/Grp'd      RW       3009B Not Visible            ???:? 16C:C1  2-Way Mir     N/Grp'd      RW       3    What does DA:IT mean in this ouput.I could figure that DA is disk director,what is IT?  Message was edited by: SymmetrixForumsModerator Removed Symmetrix ID.
what does IT mean in the "symdev list"out put