Date: Fri, 19 Apr 2013 12:58:01 -0500 From: Kevin Day <kevin@your.org> To: Scott Long <scott4long@yahoo.com> Cc: freebsd-scsi@freebsd.org Subject: Re: New Driver for MegaRaid 6Gb/s and 12Gb/s Card Message-ID: <37C12059-AF0B-47C1-AD8E-1D3B4663CD3D@your.org> In-Reply-To: <B5195BC9-0E44-4D69-AC25-EE2EC4035B4D@yahoo.com> References: <B2FD678A64EAAD45B089B123FDFC3ED75E70AC49E1@inbmail01.lsi.com> <1366236517.1499.31.camel@localhost> <B2FD678A64EAAD45B089B123FDFC3ED760761F4E25@inbmail01.lsi.com> <516FF87E.8030702@freebsd.org> <B2FD678A64EAAD45B089B123FDFC3ED760761F4FB0@inbmail01.lsi.com> <B5195BC9-0E44-4D69-AC25-EE2EC4035B4D@yahoo.com>
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On Apr 19, 2013, at 10:59 AM, Scott Long <scott4long@yahoo.com> wrote: >=20 > What will the exposed device names of the arrays be under the new = driver? Will it still be /dev/mfid* ? If it's not, then this is where = the problem lies. Many users still use device names in their /etc/fstab = for mounting all of their filesystems at boot. If you have two drivers = that will compete for the same hardware and give that hardware different = names, they will break the fstab files for those users and they upgrade = over time. A similar situation occurred several years ago with the = Intel e1000 driver; it was split into two drivers, with certain hardware = that was supported by the old hardware going to the new driver. That = broke the network configuration for many users and caused years of pain = and unhappiness as users upgraded and were hit by the switch. We don't = want that to happen here. >=20 > The real solution is that we need to have a single common naming = convention for all disks (and for network interfaces), and leave the = details of individual driver names out of the configuration part of the = system. That's not likely to happen any time soon. The other solution = is to mandate that users use volume labels for mounting their = filesystems, but that's not likely to happen either, and even if it did, = it present challenges for migrating existing users. The only remaining = solution that I can think of is to have the mfi and mrsas drivers share = the same devclass for their disk interfaces (mfid*), but that's a hack = that has not been fully explored in FreeBSD. Still, I'd encourage you = to try it and see if you can make it work. If you have any problems, = email me directly. Some Linux distributions had a flag day where upgrading beyond a certain = point caused a one-time popup asking if you wanted to convert /etc/fstab = to volume labels instead of device names. You could say no and proceed = normally, but if you said Yes it rewrote fstab to use labels. I'm not = sure where we could hook this so it happened both with freebsd-update = and source upgrades, but it would be nice to make it painless to switch.
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