Research Article

A Comprehensive Availability Modeling and Analysis of a Virtualized Servers System Using Stochastic Reward Nets

Table 2

Guard functions for VM model and VM clock model.

Guard function TransitionDefinition

gTVMfTVMfIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gTVMrepairTVMrepairIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gtVMupdtVMupdIf (#PVMMdn == 1 #PVMMf == 1 #PVMMaf == 1 #PVMMrej == 1 #PSANf == 1) 1 else 0
gTVMrestartTVMrestartIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gTVMfpTVMfpIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gTVMafTVMafIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gTVMarecoveryTVMarecoveryIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gTVMfpdnTVMfpdnIf (#PVMMdn == 1 #PVMMf == 1 #PVMMaf == 1 #PVMMrej == 1 #PSANf == 1) 1 else 0
gTVMintervalTVMintervalIf (#PVMup == 1 #PVMup == nVM   #PVMfp == 1 #PVMfp == nVM) 1 else 0
gtVMclockbacktVMclockbackIf (#PVMup == 0 && #PVMfp == 0) 1 else 0
gtVMtriggertVMtriggerIf (#PVMup == 1 #PVMup == nVM   #PVMfp == 1 #PVMfp == nVM) 1 else 0
gtVMclockresettVMclockresetIf (#PVMrej == 1 #PVMrej == nVM) 1 else 0
gTVMfprejtrigTVMfprejtrigIf (#PVMtrigger == 1) 1 else 0
gtVMuprejtVMuprejIf (#PVMtrigger == 1) 1 else 0
gTVMrejTVMrejIf (#PVMMup == 1 #PVMMfp == 1 && #PSANup == 1) 1 else 0
gTVMbootTVMbootIf (#PVMMrej == 0 && #PVMMup == 1 #PVMMfp == 1) 1 else 0
gtVMstoptVMstopIf (#PVMMrej == 1 && #PVMstop < nVM) 1 else 0
gVMreleasetVMupo, tVMfpo, tVMafo, tVMrejo, tVMsdno, tVMfo, tVMclocko, tVMpolicyo, tVMtriggeroIf (#PVMMrej == 1) 1 else 0
gtVMclockstarttVMclockstartIf (#PVMMrej == 0 && #PVMMup == 1 #PVMMfp == 1 && #PVMclock == 0 && #PVMclockstop == 1) 1 else 0
gtVMclockstoptVMclockstopIf (#PVMMrej == 1 && #PVMclockstop! = 1) 1 else 0
tVMstopIf (#PVMstop < nVM) (nVM-#PVM1stop) else 0
gTVMclockintervalTVMclockintervalIf (#PVMup == 1 #PVMup == nVM   #PVMfp == 1 #PVMfp == nVM) 1 else 0
gTVMMfpdnTVMMfpdnIf (#PHf == 1) 1 else 0
gtVMupdntVMupdnIf (#PVMMdn == 1 #PVMMf == 1 #PVMMaf == 1 #PVMMrej == 1 #PSANf == 1) 1 else 0
gTVMdTVMdIf (#PVMpolicy! = cVM && #PSANup == 1 && #PVMMup == 1 #PVMMfp == 1) 1 else 0
gTVMdrejTVMdrejIf (#PVMpolicy! = cVM && #PSANup == 1 && #PVMMup == 1 #PVMMfp == 1) 1 else 0
gTVMdTVMdIf (#PVMpolicy! = cVM && #PSANup == 1 && #PVMMup == 1 #PVMMfp == 1) 1 else 0
gTVMdrejTVMdrejIf (#PVMpolicy == cVM && #PSANup == 1 && #PVMMup == 1 #PVMMfp == 1) 1 else 0