I'm working on LLDD for a SAS/SATA host adapter, and trying to understand how the system handles link loss and recovery.
Say I have a device that gets recognized and attached as sd 12:0:4:0, at /dev/sdb. The drive goes offline temporarily, then comes back online. When it does, it comes back as sd 12:0:5:0, and maybe /dev/sdb, maybe /dev/sdc. I'm not sure how the Id gets assigned. Since this is the same drive, is there some way my driver can tell libsas and/or SCSI core that it's the same drive coming back? Or is there no way to control that? I looked into /dev/disk/by-id, but that also didn't quite do what I expected. If I open /dev/disk/by-id/some_identifier, that's a symlink to, say, /dev/sdb. /dev/sdb goes away, comes back as /dev/sdc, but my process doesn't know that, it still has /dev/disk/by-id/some_identifier opened and so it will never recover without closing and reopening the file. Thanks for any help or insight you can give. Chris Moore
