other  within  the  channels  of  a  branch  do  not  have  to  be  identical  to  each 
other  (for  example,  the  DIMMs  in  DIMM  connector  1  and  DIMM  connector 
2). 
-  Both  branches  operate  in  dual-channel  mode. 
The  following  table  shows  the  DIMM  configuration  upgrade  sequence  for 
operating  in  mirroring  mode. 
 
Table  3.  DIMM  upgrade  configuration  sequence  in  mirroring  mode 
Number  of  DIMMs  DIMM  connectors 
4  1,  4,  7,  10 
8  1,  4,  7,  10,  2,  5,  8,  11 
12  1,  4,  7,  10,  2,  5,  8,  11,  3,  6,  9,  12
 
–  Online-spare  memory  disables  a  failed  rank  pair  of  DIMMs  from  the  system 
configuration  and  activates  an  online-spare  rank  pair  of  DIMMs  to  replace  the 
failed  rank  pair  of  DIMMs.  For  an  online-spare  pair  of  DIMMs  to  be  activated, 
you  must  enable  this  feature  and  have  installed  an  additional  rank  pair  of 
DIMMs  of  the  same  speed,  type,  size  (or  larger),  and  technology  as  the  failed 
pair  of  DIMMs.  You  must  enable  the  feature  through  the  Configuration/Setup 
Utility  program.  To   enable  online-spare  memory  in  the  Configuration/Setup 
Utility  program,  select  Devices  and  I/O  Ports  →  Advanced  Chipset  Control  → 
Memory  Branch  Mode.  Use  the  arrow  keys  to  change  the  setting  for  Branch 
0  Rank  Sparing  or  Branch  1  Rank  Sparing  to  Enabled;  then,  save  your 
changes.  See  “Using  the  Configuration/Setup  Utility  program”  on  page  50  for 
additional  information.  When  you  use  online-spare  memory,  you  must  consider 
the  following  information: 
-  You  cannot  enable  online-spare  memory  while  the  server  is  operating  in 
mirroring  mode. 
-  When  you  use  online-spare  memory,  the  two  memory  branches  operate 
independently  of  each  other.  You  can  enable  online-spare  memory  for  one 
or  both  branches. 
-  Online-spare  memory  reduces  the  amount  of  available  memory. 
-  Online-spare  DIMM  pairs  are  assigned  according  to  your  DIMM 
configuration. 
-  Online-spare  memory  works  by  copying  data  from  a  failed  DIMM  rank  to 
another  good  DIMM  rank  within  the  same  memory  branch. 
-  Online-spare  memory  cannot  copy  data  from  one  branch  to  the  other.
 
Chapter  2.  Installing  optional  devices  35