From mboxrd@z Thu Jan 1 00:00:00 1970 From: Duncan <1i5t5.duncan@cox.net> Subject: Re: Wiki update request: source repo page Was: [PATCH] Btrfs: use i_version instead of our own sequence Date: Fri, 13 Apr 2012 21:55:20 +0000 (UTC) Message-ID: References: <1333986794-6525-1-git-send-email-josef@redhat.com> <20120412133107.GC1924@localhost.localdomain> <20120412215546.GB4856@carfax.org.uk> <20120413131632.GG4856@carfax.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 To: linux-btrfs@vger.kernel.org Return-path: List-ID: cwillu posted on Fri, 13 Apr 2012 14:03:38 -0600 as excerpted: > The fact is that you _don't_ know that your device names aren't going to > change one day, any more than a generation of developers who only worked > with ext3 knew that "fsync is expensive and all you really need is the > atomic guarantee of mv". What I /do/ know is that such changes will be due to either (1) kernel upgrades or (2) hardware changes (planned upgrades or unpredicted failure). Both factors can be mitigated with redundant layers of fallback and dynamic reconfiguration. Regardless of what brings those device names, a fallback to an earlier kernel, or a different device, or a bit of manual grub commandline new device location detection and according alteration of the grub-passed kernel command line so I can boot and make the necessary permanent config changes, is all it'll take to change that. And as an admin working with stuff directly within my reach to fix when necessary, unlike that generation of developers on ext3 with expensive fsync, once it's out of my reach to directly manipulate for a fix, it's no longer something I need to worry about. Granted, btrfs and distro devs have to worry about products out of their direct reach to fix, but that doesn't mean they have to take the tools away (or even simply hide them) from those that can and do put them to use. > Everyone needs to start somewhere, but it's not unreasonable to expect > an admin to understand how their distro does things, and where to find > answers when they don't know, and to verify that their knowledge is > correct. The middle of a disaster recovery should not be the first time > you've tried a recovery. Agreed. That's why a prudent admin continually scans the radar for incoming, as well as having tested fallbacks for the unexpected. Either that, or as I was at one point, they don't have the knowledge or experience yet, but are willing to risk loss of data and a new install, in ordered to get that knowledge and experience. I remember being in that group myself, and to a certain extent, I'm still a part of it. After all, that level of risk and the knowledge and experienced gained from it is part of the pull of pre-releases, live-git kernels, and experimental filesystems, in the first place. But that doesn't mean I don't try to control that risk by building on knowledge and experience I already have to limit the risk stack at other levels. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman