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Ext4 Filesystem Enters Experimental Kernel Tree
Posted by
timothy
on Fri Oct 13, 2006 07:08 AM
An anonymous reader writes "Looks like the next version of the venerable Linux 'ext' filesystem is just around the corner. Andrew Morton has added an early version of ext4 to his 2.6.19-rc1-mm1 tree, enabling Linux to support storage volumes up to 1020 petabytes in size, and to write files in 'extents,' or contiguous, reserved areas. According to an article at Linux-Watch, ext4 will be ready for production use within six to nine months, if all goes well. On the downside, the new ext4 filesystem will offer only limited backward compatibility with ext3-aware Linux kernels."
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Reiser4 (Score:3, Funny)
Re:Reiser4 (Score:5, Insightful)
As much as I agree with you questioning the many 'funny' ACs, I can't support this statement. One day you, yes, you, might also become a suspect. And then, suddenly, you would see the world with different eyes. Especially, when you're found innocent and you also find that your friends have deleted all memories of you since they don't want to be associated with you; as suspect.
I am sure many of us would feel similar once the investigation is over and Hans eventually found guilty. But as civilised people, we better wait. How old are you ? Have you never ever been suspected of something ?
Parent
Re: (Score:3, Informative)
Though, the author must be a programmer and the reader must count opening and closing quotation. > 80% of the comment is quotation, right, and in the end the author of parent says Even if he is convicted that doesn't mean he is guilty.
That makes my comment bad, but not the mod. It makes the comment redundant for copy & paste of another post to finally say "I don't agree with this".
1020 Petabytes? (Score:5, Funny)
Not to be confused with Excitebike, which is something entirely different.
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On second thought, maybe it is Informative, since I was not previously aware you could cram that many puns into so few words.
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That's 6, and
fsck (Score:5, Funny)
FSCK (Score:2, Troll)
1020 petas (Score:2, Funny)
My porn collection will now be complete.
Re:1020 petas (Score:5, Funny)
My porn collection will now be complete.
Liar... there is no such thing as a complete porn collection!
Parent
Re: (Score:2, Interesting)
Here is why:
Suppose you want to watch porn 24 hours a day from the age of 15 till 75. Thats 60 years = 60 * 365.25 * 24 * 60 * 60 s = 1.89 * 10^9 s
A DivX is around 600 MB / hour = 600 * 1000000 / (60 * 60) = 1.67 * 10^5 B/s
So for your lifetime porn collection you need 1.89 * 1.67 * 10^14 B = 315 TB.
performance (Score:4, Interesting)
Advantages over XFS, for example. (Score:5, Informative)
XFS can do 9 exabytes (exabyte = 1024 petabytes).
They mention that ext4 is not faster than other filesystems.
Ofcourse people can do whatever they want, but why not spend their time making XFS easily resizable for example?
Re: (Score:3, Interesting)
I would also appreciate block journaling for XFS.
Re: (Score:2, Insightful)
You mean, "exbibyte = 1024 pebibyte". An exabyte is exactly 1000 petabyte.
I used to think this was just fussy, but I am quite tired of guessing which system producers of hard disks/CDROMs/DVD+±×RWs use to figure out if that is enough for my needs.
features isn't everything (Score:3, Informative)
Simple: ext4 is a backwards compatible, evolutionary change from ext3, while XFS is a different file system and codebase. XFS doesn't offer sufficient advantages to overcome that built-in advantage of ext4 (after all, neither XFS nor ReiserFS managed to succeed even against ext3).
Wow (Score:3, Funny)
Now, is there anybody who still believes that porn does not drive innovation?
also in linus tree (Score:2, Informative)
Also merged is the developmental ext4 filesystem, which includes a number of enhancements, including support for extents and 48-bit block numbers. See the ext4 documentation file if you are interested in playing with ext4 (and have good backups).
And how... (Score:5, Insightful)
I'm honestly more interested in someone coming up with cheap, long term archival storage. Hard disks have gone so far past our ability to archive information it's beyond comprehension.
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Harddiscs are, as you say currently superior to other storage-technologies.
So, you make backups to hard-disc then. Simple. Quick. Affordable.
Yes, the lifetime is limited, so you should make sure to have atleast 2 independent backups (that's true for any media, all media can go bad) and you should change them every 3 years or so.
The thing is, capacity is growing so rapidly, that in 3 years, what is now a hard-disc full of backup will be a hard-disc 10% full of backup.
I need
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20 years ago you would ask the same thing about 500 MB hard disks. And don't forget the article (or at least the sumary, as a good slashdotter I don't RTFA) says about the file system capacity, not the real capacity of hard disks. Petabytes hard disks are something for the future, not for now.
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You buy ten of them and do a super-redundant RAID.
I knew a guy... (Score:3, Funny)
rm -rf
It never occurred to him (or me) that ".." matched that pattern. He worked his way right up the directory tree and back down again...
extents (Score:2)
Aright! 1970s mainframe technology, here we come!
Re: (Score:2, Informative)
With EXT4 having extents we'll finally have the joy of defragmenting a hard drive like Windows people. Yea, progress!
Interesting in light of OpenSuSE's decision... (Score:5, Interesting)
to no longer use ReiserFS [wordpress.com] as its default FS (orig. reported on OSNews.com [osnews.com]...don't think I've seen it here yet). I think this came out before the whole Hans Reiser affair, BTW.
SuSE contrasted the ease of upgrading ReiserFS and ExtFS versions:
Experimental?? (Score:2, Interesting)
Novell Suse prefers Ext3/Ext4 over ReiserFS 3 / 4 (Score:4, Interesting)
Other Reiser issues aside, the SuSE folks at Novell are looking to leave [linux.com] the nearly unsupported reiserfs3 (in maintenance support, which isn't enough for them) and move to ext3 as their default FS. Why? They feel ext3 is a lot more mature & better/wider supported then reiserfs4, is an easier migration, and appreciate that there is a solid roadmap from ext3 to ext4.
Of course this would also be the week that (coincidentally) Andrew Morton gives reiserfs4 the green light [apcstart.com] for eventual mainline kernel inclusion.
So funny (Score:3, Informative)
Ext4 is going to be the MOST compatible with Ext3, relative to ANY other option out there.
Upgrading to Ext4 is NOT going to involve a dump and restore from Ext3, likely a tunefs -j or similar command, just as the ext2 -> ext3 migration worked. Ext4 will be able to mount ext3.
If older versions of software could use the new format, you wouldn't need the new format. Yes, upgrading to Ext4 means your 120 petabyte raid array will not be compatible with your old "ext3 aware kernel". But it is PRECISELY because such an array is not possible under ext3 that ext4 is going to be introduced.
And does this submitter think other fancy new filesystems magically work on old kernels? Of course not. Does the submitter know if ext4 will be backported and made available to older releases? It doesn't look like they gave that much thought either.
Please read this [lkml.org] for a more detailed description of what is happening.
Slashdot's always good for a smile.
Re: (Score:3, Informative)
The article says "On the downside, the new ext4 filesystem will offer only limited backward compatibility with ext3-aware Linux kernels."
Well if you had a clue, you would know that this is in reference to the fact that you can mount a ext3 file system as ext2 from a kernel that doesn't have support for ext3. It just doesn't journal. They were simply stating that this rather useful feature that made ext2->ext3 migration so painless will likely not be as simple in ext3->ext4 migration.
With that in m
Re:1020 Petabytes? (Score:5, Insightful)
By now you don't even now what to do with 1024PB. Just as we couldn't imagine filling a 250GB harddrive 15 years ago when 500MB were considered huge.
What will happen? We store our digital photos in raw format, not JPEG. We store our songs in raw format, not artificially crippled. We will store high-definition video, possibly even in raw format, not MPEG4 or the likes.
And, woosh, 1024PB will be nothing leaving us wondering how we could ever survive with a measly 250GB drive -- just as we ask ourselves today how life was with nothing but 170kB disk drives.
Parent
Re: (Score:3, Interesting)
I'm not convinced by this myself. I do however see a need for super computers who need to work with filesystems spanning perhaps hundreds of disks. As for the desktop user, even if they did store their files in raw format, I doubt they'd use more than a few 10's of terabytes at the most.
Re:1020 Petabytes? (Score:4, Informative)
framedimensions = 3000 x 2000
framebytes = framedimensions x 6
moviebytes = framebytes x 25 x 60 x 120
moviebytes / 10^12 ~= 6.5
Parent
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Tom
Re: (Score:3, Interesting)
Super computers? Once, maybe - not today, and not for the last decade or so. There are a bunch of companies (I'm working for one of them [netapp.com], now) that will quite cheerfully sell you a storage system that spans hundreds of disks [netapp.com]. Assuming your OS won't flake out when it sees a 500+ TB volume, you could mount it on your desktop, if you want. There's absolutely no need to conflate processing pow
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Re: (Score:2)
Unless you are publishing your audio, videos or photos you don't need a 100% representation. Often that 97% quality but 1/10th the size copy will be fine for your own enjoyme
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Re:1020 Petabytes? (Score:5, Insightful)
The limits are set by our senses, more concretely, our ears and our eyes.
Our ears are only capable of hearing up to about 20Khz (less than that for most people) and 16-bit samplings are enough that most people cannot hear the difference with anything more. Thus CD-quality is, if not perfect, then good enough that further improvements are ignorable for most people. CD-quality losslessly-compressed music is around 300MB/hour.
In a year, there's 8760 hours, so you'd need on the order of 2.5 TB to store a year worth of around-the-clock never-repeateing losslessly-compressed music. If computers keep getting replaced at the current rate, this means you'll never need more than about 10TB to store sound. This assumes you don't store more than you listen to, if you choose to for example store all music ever produced for convenience, despite never listening to more than a tiny fraction of it, then this requirement goes up by a couple of orders of magnitude. Still, there's good reason to suppose that 10TB will suffice for most peoples sound-storage needs. (even if you wanted to store all the sound you've *ever* heard in your life, including traffic at nigth, that'd still only be 200TB or so)
The real killer is video. We can take in a *lot* more data with our eyes. 10GB/hour is in the ballpark of what you'd need for the sort of quality a modern cinema can deliver. (and there's no particular reason we couldn't go higher.) That works out to 100TB/year, more or less. A lifetime of high-quality video is thus on the order of 10PB.
In short, it is unlikely that an individual (or family) will be able to fill a 1000PB disc with sound and video-recordings. Infact it's unlikely they'll be able to fill it with anything, if that anything is to be consumed only trough their 2 eyes and 2 ears.
That doesn't mean it won't happen. Only that it'll be filled with something more. Once we fire up the holodecks all bets are off. I don't even want to try to estimate the bandwith needed for that kind of immersive experience.
Parent
Re: (Score:3, Funny)
People always used to ask me if I had the internet at home. Maybe when I can get my hands on a 1020 PB hard drive, I will be able to download it all for local access...
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find "$dir" -amin +"$time" -print0 | xargs -0 rm -fr
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Re: (Score:3, Insightful)
First of all, disk drives are advancing faster than tapes.
But the problem is worse than that. Different aspects of disk drives are advancing at different rates. Capacity is increasing faster than interface speed is increasing faster than access speed is increasing faster than block reliability.
Consider an old 500MB drive from the mid-90s; it takes maybe a couple hours to read every block on the drive, and odds are that you won't have bad blocks before the disk dies entirely.
The new
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Have you heard of porn? Yeah, I didn't think so...