Specifications

2
Software Architecture
33
Shelf cooling
Toensurethatallmodulesintheshelfoperateefficiently,theiroperationaltemperatures
mustbemaintainedatoptimallevels.Allmodulesaff ectedbyon‐boardtemperature
fluctuationshavesensorsthatgenerateeventsincasetheiroperationaltemperaturescross
pre‐setthre sholdlevels.Temperaturesensorsgenerateeventsatthreedifferentthreshold
levels:Minor,Major,andCritical.
TheactiveShelfManagerregistersasaneventreceiverwithallintelligentshelfcomponents
inordertoreceivealltemperatureeventsgeneratedbysensorsintheshelf.Itusesacooling
algorithmtomakeadjustmentstothecoolinghardwaretomaintainoptimalcomponent
temperatureswhileminimizing noiselevels.
Summary of supported cooling hardware
Table 2identifiesthecoolinghardwareforeachRadisysshelf.Inthisdocument,alltypesof
coolinghardwarearereferredtogenericallyasafans.
Shelf Manager cooling algorithm
Atshelfpower‐up,thefansrunatclosetofullspeedasasafetyprecautionagainst
overheatingbeforetheShelfManagertak escontrol.TheactiveShelfManagerthenprograms
allfanstooperateatapercentageoftheirmaximumspeedbeforeitstartsreceiving
temperatureevents.OncetheactiveShelf
Managerisfullyinitialized,thefanspeedsare
reducedandremainthereuntilatemperatureeventisreceived.Afanfloorsetting
determinesthelowestfanspeedtheShelfManagerwilleverset.
Minorandmajortemperatureeventassertionscausethefanspeedstoincreasein
incrementsuntiltheconditioniscleared.TheShelfManagerraisesthefanspeedonelevelfor
aminortemperatureeventandtwolevelsforamajorevent.Ade‐assertioneventfromthe
samesensorindicatesthattheconditioniscleared,andthefanspeedisdecrementedone
levelatatime—aslongasnotemperatureeventsareasserted—backtothelevelofthefan
floor.Fanspeedchangesarereducedovertimebyadjustmentstothefanfloor,asexplained
inAdaptivefanflooralgorithmonpage 34.
WhentheShelfManagerreceivesacriticaltemperatureevent,itattemptstopoweroffthe
moduleassociatedwith
thesensor.Evenwhilepoweredoff,thesensorsare stillfunctional.
Thealarmconditionmaynotbeclearedimmediately,ifatall,sothefansmaycontinuetorun
atahighspeed.
Table 2. Cooling hardware controlled by the Shelf Manager
Radisys shelf Cooling hardware
ATCA-6000 Four air mover modules (AMMs), each controlled separately.
ATCA-6006 Two fan trays, each controlled separately. Each fan tray contains multiple fans that cannot
be separately controlled.
ATCA-6002 The fans in this shelf always run at full speed and are not under Shelf Manager control.
ATCA-6014 Three fan trays that contain multiple fans. All of the fan trays in the shelf are controlled as a
single unit.
ATCA-6016