On Fri, 2007-10-05 at 15:17 -0700, David Miller wrote: > From: James Bottomley <[EMAIL PROTECTED]> > Date: Fri, 05 Oct 2007 18:14:48 -0400 > > > On Fri, 2007-10-05 at 15:11 -0700, David Miller wrote: > > > auto_wwn=1 or somthing like that > > > > I'd far prefer > > > > override_wwn = <fully specific WWN> > > > > since I assume auto_wwn means get the kernel to generate one? > > I think providing both possibilities (kernel auto-generated and user > specified) is appropriate.
My problem with auto generated is that it's provably impossible to generate globally unique numbers for WWNs without some internal source of uniqueness (I know sparcs have this in their serial number, but most PCs unfortunately don't). I know the auto generated number can be statistically reasonably unique, but sysadmins are lazy people. If they run into this problem, they'll take the knob with the on/off switch rather than the think about the problem and specify the full WWN; and then, being busy people, they'll forget about it as "problem solved". When they do this, statistically (and probably years later) there will be a cluster reboot where the entire SAN simply collapses and no-one knows why ... the poor SAN administrator will likely spend weeks working out the problem is. I'd rather not give an interface which seems like a magic bullet but which is a potential time bomb in a cluster (particularly when it has such a long fuse). James - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
