# FreeBSD IFF_RUNNING??



## Chi Min Wang (May 27, 2018)

Hello Everyone:
      I am trying to use HAST with UCARP to archive storage/service level HA. If I stop UCARP service or shutdown any node,the primary/MASTER and secondary/BACKUP could switch over correctly. However,if I disconnect the Ethernet,the kernel detect link down,but the UCARP MASTER node just remaining in MASTER mode(it should be switching to BACKUP mode,and the HAST relies UCARP to switch it to secondary mode). Even more,if I disconnect Ethernet of the BACKUP node,then it will switch to MASTER mode(due to receiving no MASTER advertisement). This will cause huge chaos when both node become online again(since there is no timestamp in the HAST's metadata)....

I  found the subroutine docarp(void) in carp.c of UCARP use IFF_RUNNING flag to determine when the MASTER node should switch to BACKUP mode....






Does the IFF_RUNNING flag indicates the interface is really usable,or what's the "resorces allocated" meaning?? Thanks!!


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