Ext4 Filesystem Enters Experimental Kernel Tree

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."

performance

[bioglaze]

How does ext4 perform when compared to, say, reiserfs 3.6 or 4? What new features there are?

Re:1020 Petabytes?

[astralbat]

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.

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:Advantages over XFS, for example.

[Zarhan]

Ofcourse people can do whatever they want, but why not spend their time making XFS easily resizable for example?

I would also appreciate block journaling for XFS.

Re:1020 Petabytes?

[CastrTroy]

This is exactly how I'm filling up my space. I got a new computer with a 160 GB drive, thinking it would be "enough". Started storing all my CDs in FLAC, and I'm currently transfering all hte movies I downloaded in AVI to DVD so I can watch them easily on my home theatre. Once you start working with video and sound that isn't compressed to nothing, you start to realize just how fast you can use up all that space. If my camera did RAW i'd probably use that to store my photos. I usually save any edits I do in PNG or TIFF so that I don't have to worry about the lossy encoding. Granted I still have space to spare, but I could see very easly using up a Terabyte drive if I had it, and a faster internet connection.

Interesting in light of OpenSuSE's decision...

[Saint Aardvark]

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:

ReiserFS v3 is a dead end. Hans has been pushing reiser4 for years now and declared Reiser3 in maintenance mode. Any changes that arent bug fixes are met with violent resistance. Reiser4 is not an incremental update and requires a reformat, which is unreasonable for most people.... Ext3 has a clear upgrade path. There is quite a bit of interest in the community in improving ext3, and ext4 is already under development. Like the upgrade path from ext2 to ext3, the path to ext4 is clearly defined. Existing file systems can be updated easily, and new files will be able to take advantage of the new features.

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[account_deleted]

Comment removed based on user account deletion

Re:1020 petas

[tonigonenstein]

My porn collection will now be complete

In fact, 315 TB should be enough for anybody.

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.

Novell Suse prefers Ext3/Ext4 over ReiserFS 3 / 4

[maggard]

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.

Re:1020 Petabytes?

[Samrobb]

I do however see a need for super computers who need to work with filesystems spanning perhaps hundreds of disks.

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 power (super computers) with storage capability (NAS, SAN, etc.)