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Whither btrfsck?Whither btrfsck?Posted Oct 11, 2011 20:59 UTC (Tue) by jcm (subscriber, #18262)Parent article: Whither btrfsck?
I might be old fashioned... :)
I learned a long time ago that you want your data on tried and tested technology and filesystems. Years ago when I was first getting into doing sysadmin stuff part time in college I thought it would be fun to run upstream kernels on a production system built on reiserfs. Yea, those were the days. Then I grew up. Now, no matter how hard you convinced me, I wouldn't choose to use btrfs for data I cared about (and I wouldn't run random kernels either). It's nothing to do with the developers (who I'm sure are doing great work) and everything to do with the same reason I haven't had Lasik yet. I'm going to let many other people beta test and learn their own lessons from the experience, so I don't have to do that all over again.
But also, nobody will listen to things like the above. So yes, some stuff is too dangerous to be released. Someone will install and use it no matter how many warnings you put on it. And when they do, they'll forever hate you when it behaves exactly as you said it would. Like how I would never use reiserfs again no matter how good it claims to be. It ate my data once, so it will never be getting a second chance.
Jon.
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Whither btrfsck? Posted Oct 11, 2011 21:23 UTC (Tue) by fuhchee (subscriber, #40059) [Link]
"It ate my data once, so it will never be getting a second chance."
Do you think it is practical to have that strict-sounding an attitude with more mainstream parts of linux? Ever had a data-corruptor kernel bug? Or a crash with a corrupted filesystem? Or a hard drive model fail?
Whither btrfsck? Posted Oct 12, 2011 0:13 UTC (Wed) by PaulWay (✭ supporter ✭, #45600) [Link]
The problem is that people do have this attitude. I work with developers who don't like Red Hat because of what they did in 1999. I work with people who prefer Debian because of "RPM Hell". I've worked with people who hate Perl because of the quality of code written in Perl 3. I've worked with people who have sworn never to use a Seagate disk because of that great problem they had back in 2003 or whatever.
To repurpose http://xkcd.com/242/, maybe scientists can afford the time to see if the same problem happens again later. But sysadmins and programmers tend to be under pressure to produce results, and lots of them can't afford the time to retest their assumptions later. The better ones I've seen test new things out or test their assumptions out at home or on test systems in spare time. The cowboys test them on live systems in production and then wonder why everyone gets upset.
I agree we should all be able to test out btrfsck and have the code in the open so that people can contribute ideas about those corner cases and weird fuzzy problems that Chris might not have thought about. But if there are already people complaining that btrfs is eating their data, then releasing btrfsck early and buggy is only going to hurt its reputation. That's why I support Chris's decision to hold onto it for now. I'm sure he's trying to do the right thing but it's his decision to make.
Have fun,
Paul
Whither btrfsck? Posted Oct 12, 2011 19:46 UTC (Wed) by Baylink (subscriber, #755) [Link]
Paul: that argument seems like it would support Chris *not releasing the FS code*. But as the article makes clear, that wasn't the case. It's *only* the fsck that's not in the wild.
Whither btrfsck? Posted Oct 12, 2011 0:52 UTC (Wed) by jcm (subscriber, #18262) [Link]
As Paul points out, people have this attitude (and I'm one of them sometimes). I'm a scientist and I'm all for zapping myself with magic lightening machines (see xkcd reference cited below) on my own dime and at home, but if I were a sysadmin again I wouldn't be doing that with other people's valuable data. I'd be saying "gee, reiserfs bit me once so now it has to go out of its way to prove that I should use it over something I know is just going to work". This is also why in the real world people are still running OS releases from several years ago, and why they want them supported for the next million years. Because it works and that's all they want.
Whither btrfsck? Posted Oct 12, 2011 8:23 UTC (Wed) by arnd (subscriber, #8866) [Link] I think that's all fine, as long as we have enough people zapping themselves with btrfs in their homes[1]. A problem that I frequently heard cited with mainframe OSs is that every customer buys the latest release the moment it comes out and then waits for six to twelve months before installing it since they know it is less stable than what they want.This makes absolute sense from an individual customer's point of view, but is extremely counterproductive on a global scale since many bugs that matter in real life only get found in real-life conditions. At this point I would like to thank everybody who is running the latest kernel or distro snapshots and writes bug reports about them. [1] Me included, will gladly donate broken root fs image to btrfsck testing now that I copied all the readable data to a new partition.
Whither btrfsck? Posted Oct 12, 2011 19:47 UTC (Wed) by Baylink (subscriber, #755) [Link]
I Am Not A VM Guy... but what I know of them suggests that
> A problem that I frequently heard cited with mainframe OSs is that every customer buys the latest release the moment it comes out and then waits for six to twelve months before installing it since they know it is less stable than what they want.
isn't actually true: I would assume the load the new OS in a VM or LPAR, and dump test loads on it to see if it works, before promoting it to production.
Hardware-level virtualization makes that stuff easy...
Whither btrfsck? Posted Oct 12, 2011 20:19 UTC (Wed) by arnd (subscriber, #8866) [Link]
You're right, I oversimplified. What tends to happen is that people wait half a year after the release, then install the new OS into a test partition and test for another six months before putting the system into production.
The times are obviously different depending on how paranoid the admin is and on the type of workload.
However, there are still good reasons for waiting: The bugs you encounter while running the new software on your test partition are often different from the bugs that other people encounter while running the same software in production. If you care a lot about stability, you probably want to have both kinds of problems solved before you get to the point of no return.
Whither btrfsck? Posted Oct 13, 2011 13:35 UTC (Thu) by pspinler (subscriber, #2922) [Link]
Speaking as a VM guy, you're mostly right, except that we do our new releases in a 2nd level virtual.
VM is pretty cool, and it makes a neat platform to run linux on. :-)
-- Pat
Whither btrfsck? Posted Oct 13, 2011 15:06 UTC (Thu) by Baylink (subscriber, #755) [Link]
And that's a conversation I'd like to have with Someone Who Knows, off line, in much greater detail, Pat... :-)
Whither btrfsck? Posted Oct 11, 2011 22:21 UTC (Tue) by SEJeff (subscriber, #51588) [Link]
<sarcasm>
LASIK was approved by the FDA in 1995. Do you run RHEL 2.1 (released Oct 1995) in production because you're letting other people beta test this new stuff like RHEL4? </sarcasm>
Even though many people see Oracle's Unbreakable Linux as CentOS with a nice kernel, that doesn't mean Oracle isn't doing some absolutely bleeding edge Linux work. For them to commit to officially supporting btrfs in their OEL builds means that they'll commit to supporting it in real production environments. That does say an awful lot about it coming from the company who employs the lead developer of said filesystem.
Give it a year or two of solid beating and it will be good to go. My personal take is that if ext4 gets stable snapshotting support, it will be good enough for most people.
Whither btrfsck? Posted Oct 11, 2011 22:33 UTC (Tue) by dlang (✭ supporter ✭, #313) [Link]
and how exactly did the FDA test what happens to people's eyes 40 years after the LASIK surgery? how do you really know that you aren't trading the inconvenience of wearing glasses for some years of blindness later?
being wary of LASIK for something irreplaceable like your eyes is not completely unreasonable.
Whither btrfsck? Posted Oct 11, 2011 22:38 UTC (Tue) by corbet (editor, #1) [Link] What?? You mean you didn't back up your eyes before letting the Lasik people hack on them?!? I bet you didn't wait for the repair tool to be ready either.Actually, for some of us, being able to restore our eyes to a 40-year-old backup starts to sound pretty nice. That said, I'm not sure how apt the comparison really is...
Whither btrfsck? Posted Oct 11, 2011 22:49 UTC (Tue) by SEJeff (subscriber, #51588) [Link]
Not being an opthomologist, I am the wrong person to ask. However, since Dr Caster (the guy who wrote *the* book[1] on LASIK and performed my procedure) had the surgery himself, chances are the effects are understood well enough. . LASIK is a physical procedure, not something like a medicine which may cause kidney damage 40 years down the road. It either works, or it doesn't.
However this is way off topic and I was only using that reference in jest. The parent commenter has good reasons for his opinion as some people are more risk adverse than others. This is LWN, not /., lets talk more about the tech.
[1] http://www.amazon.com/Lasik-Miracle-Complete-Better-Visio...
Whither btrfsck? Posted Oct 12, 2011 2:01 UTC (Wed) by jg (subscriber, #17537) [Link]
I sat next to an opthamologist who specialized in LASIK one trip; turns out the basic operation of using a microtome goes back a very long way, so they had very high confidence about the very long term consequences of opening up the eye since it had been done for many decades for other reasons, The only twist was adding the laser to precisely control the material removed.
Whither btrfsck? Posted Oct 12, 2011 22:18 UTC (Wed) by rahvin (subscriber, #16953) [Link]
PRK and it's predecessors were in wide use in the early 80's and it was developed far earlier. What they did and what Lasik does are only different in the tool used to make the cuts. The stuff in the early 80's was done by hand with scalpels in a hospital, today it's done in an outpatient surgery through the lens with computer controlled lasers using layouts developed mostly by hand in the 80's. The most recent versions of Lasik now can map and create custom modifications of the standard cut patterns.
But basically the procedure's been in use for more than 30 years. Considering the procedure isn't even recommended until your 20's and myopia sets in at 40 the effects of Lasik on aging eyes are well understood at this point. If you are avoiding Lasik because you think it's long term effects aren't known you really need to look into it more and understand the history.
My wife went from about 20-400 with an astigmatism (before surgery got worse every year) to 20-15 and hasn't had a single problem (other than the night halos which are guaranteed). In her opinion it was the best 3 grand we ever spent. She can even see better than me and her vision is fixed by the scars, other than age related myopia her vision will never change.
OT: myopia vs. presbyopia Posted Dec 6, 2011 4:54 UTC (Tue) by Duncan (guest, #6647) [Link]
Myopia (near-sightedness) setting in in one's forties? Umm... Not commonly.
More like presbyopia, age related loss of focus/accommodation ability for near work, reading and the like, typically noticed first in one's 40s reading small print in dim light, and generally thought to be related to loss of crystalline lens elasticity.
There's also hyperopia aka farsightedness. Presbyopia is often called farsightedness as well, tho presbyopia is a special term for the age related loss of lens flexibility and thus near focus.
I'm highly myoptic (-11-ish diopters, too much so for good lasik results) with astigmatism (irregular or toric curvature of the cornea or lens, thing American football shaped). Hard (gas-permeable) contacts correct more accurately for the astigmatism and give me a much wider field of view without the peripheral distortion of glasses at the required corrective values. I'm also in my mid-40s and need reading glasses to reduce the contact correction (calibrated for distance vision) by a couple diopters (so to -9-ish, still highly myoptic), thus have personal experience with astigmatic myopia from early childhood, and presbyopia for a half decade or so. Thus my personal knowledge of the subject.
Wikipedia and google of course have more.
Duncan
Whither btrfsck? Posted Oct 12, 2011 23:05 UTC (Wed) by gdiffey (subscriber, #65017) [Link]
and you can now do it yourself at home!
Whither btrfsck? Posted Oct 13, 2011 8:02 UTC (Thu) by hickinbottoms (subscriber, #14798) [Link]
Off topic, but I particularly enjoyed how the guy holding the device on that website is still wearing glasses. Nice touch.
Stuart
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