On 10/09/2018 01:49, Don NetBSD wrote:
I've done a lot of work with SAS disk enclosures that support SES. They often have an SES command that can turn off the drive in a bay prior to removal (but support is optional).I'm not concerned with automatically detecting insertion/removal; that's the job that the operator performs (above) -- along with the tagging of the media, etc.
A SCSI stop unit command may spin down a SAS disk but its not guaranteed as it depends on whether or not the SAS HBA or expander is sending the drive periodic NOTIFY primitives (which trigger drive spinup). What works with one SAS HBA may not work with a different one.But, I'd be concerned about pulling a drive that was still *spinning*. atactl(8) doesn't seem to work with sd(4) devices. I'll have to see if drvctl -d spins the drive down as it is disconnected (and maybe a timeout to ensure the operator doesn't remove the drive before its had a chance to spin down sufficiently)
On a more practical note. As long as you disconnect the drive from the connector gently and give it 5-10 seconds to spin down before any significant movement SAS/SATA drives tend to survive removal even if they are spinning.
In SAS hotplug is not optional. ALL SAS HBAs should support it regardless of whether the drive is directly plugged in or in some of drive carrier. I don't know if NetBSD will deal with these events though.
Mike