Patent ID: 7912995

Claim:
A method for use in managing SAS (Serial Attached SCSI) topology, comprising: internally within at least one SAS device on a SAS network, monitoring a performance characteristic of a PHY of the SAS device, wherein the SAS device is connected to a storage controller within a data storage system through at least one SAS expander, wherein the data storage system comprises at least two chassis or enclosures connected through a pair of SAS cables, the chassis or enclosures having the SAS expander; internally within the SAS device, determining, based on the performance characteristic, that the PHY is in a problem state; internally within the SAS device, putting the PHY under probation by initiating a probation timer based on the determination affecting the PHY to help prevent the PHY from adversely affecting communications between the chassis or enclosures on the SAS network; based on the probation timer, if the PHY stays in probation longer than a specified time interval without entering recovery, disabling the PHY; internally within the SAS device, entering recovery by initiating a recovery timer if it is determined that the problem has gone away after initiating the probation timer; based on the recovery timer, cancelling the recovery timer if the PHY is determined to return to the problem state; and internally within the SAS device, terminating the probation timer and the recovery timer if the recovery timer exceeds a specified time interval, wherein terminating the probation timer and the recovery timer means that the PHY is assumed to be good.