Dell Compellent 55
3 Connect the Back End
EnclosuresareconnectedtocontrollersusingSAS,apoint‐to‐pointswitchedtopologyon
fourlanes.EachlanecanperformconcurrentIOtransactionsat6Gb/sec.DellCompellent
recommendsconnectingtheSASdriveenclosurestothecontroller(s)usingthemost
redundantoptionsthatareavailable.
Contents
SASEnclosureCablingGuidelines ............................................. 55
ConnectIPC
forDual‐ControllerStorageCenters ................................ 56
ConnectSC200/SC220Enclosures ............
.................................. 60
ConnectSC280Enclosures ..............
...................................... 75
ConnectEN‐SASx6x12/24Enclosures ........
.................................. 84
LabeltheBack‐EndCables ............
........................................ 93
SAS Enclosure Cabling Guidelines
MultipleSASenclosuresareconnectedtoacontrollerbycablingtheenclosuresinseries.A
seriesofinterconnectedenclosuresisreferredtoasachain.Eachchaincancontainupto
1686GbpsSASdrives.
ASASchainbeginsataninitiatorportinacontrollerIOcardandconnects
tothefirst
enclosure.Subsequentenclosuresareconnectedinseries.Forsingle‐controllerStorage
Centers,thechainendsatthelastenclosure.Fordual‐controllerStorageCenters,thechain
endsinatargetportintheoppositecontroller.
SAS Redundancy
RedundantSAScablingensuresthatintheeventanIOCardorportfails,IOcontinuesto
flowthroughtheremainingfunctioningpath(s).Fordual‐controllerStorageCenters,
redundantcablingalsoprovidesprotectionforcontrollerfailures.Toachieveredundancy,
eachSASchainismadeupoftwopathsthatarereferred
toastheAsideandBside.