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Best Shrinkable ReiserFS Replacement?
paulkoan writes "I have been using ReiserFS for my file system across a few servers for some time now (follow the link below for details of my experience). I can't foresee the future of ReiserFS, but if I'm going to have to migrate as support diminishes, I'd like to begin that process now. My criteria are: in-kernel support, shrinkable, and has good recovery when the file system is not closed properly. That shrinkable requirement precludes a lot of options. What's a good replacement for ReiserFS?"
I initially chose ReiserFS because I was building a MythTV system and it was the recommended FS across the board, from small to large files. I've had good experiences with ReiserFS and it has had a pummeling. That MythTV box for example has a very volatile environment and loses power on a regular basis. I haven't lost any data through any of these outages.
Compare this to my brief foray into XFS on the same box, where 25% of the filesystem ended up in lost+found with numbers for filenames. When this happened a second time on a different system I decided XFS wasn't for me — and I really don't get the point of a journalled filesystem that will keep data relatively safe, but then remove any means to identify it when things go wrong.
But everyone has good and bad experiences with filesystems, ReiserFS included. XFS has a good rep, my experience aside.
I initially chose ReiserFS because I was building a MythTV system and it was the recommended FS across the board, from small to large files. I've had good experiences with ReiserFS and it has had a pummeling. That MythTV box for example has a very volatile environment and loses power on a regular basis. I haven't lost any data through any of these outages.
Compare this to my brief foray into XFS on the same box, where 25% of the filesystem ended up in lost+found with numbers for filenames. When this happened a second time on a different system I decided XFS wasn't for me — and I really don't get the point of a journalled filesystem that will keep data relatively safe, but then remove any means to identify it when things go wrong.
But everyone has good and bad experiences with filesystems, ReiserFS included. XFS has a good rep, my experience aside.
I've heard good things about ZFS from Sun Microsystems, though I don't have much experience with it. Ext3 seems to have decent crash recovery though it requires fscks almost every time. JFS2 from IBM is the most solid filesystem I've ever seen, but I don't know if such a filesystem works with MythTV.
My fastest way of checking what operations can be supported on filesystems at the present is by checking what gparted can do. Of the filesystems it works with right now, only four (jfs, reiser4, ufs, xfs) can't be shrunk using gparted.
For my MythTV installation, I choose ext3 for the system partitions like / and /usr and xfs for my /video partition. My system partitions are on a RAID 1 while my /video partition is a 1TB RAID 10 LVM. ext3 is more than adequate for my purposes and it does a decent job of recovery. Earlier this year my server started crashing intermittently with no messages in the error logs. I finally traced it to a bad stick of RAM and ext3 recovered in most of the cases. In one case I had to repair mysql databases, but that was the only hiccup.
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Ext3 with LVM seems to be the popular way to go about this. Unless you really want an esoteric solution, from your requirements I don't see a reason to stray from the norm.
Ugh, ReiserFS and "good recovery when the file system is not closed properly"? It doesn't even have good recovery after a proper shutdown.
When other filesystems die, the damage is localised. When Reiser fucks up, all or nearly all of the tree is lost. Usually, you'll lose all files bigger than 4KB, although other damage modes are possible.
Reiser has a codebase of an insane size. A relatively small piece of code can be mostly bug-free, Reiser is simply too large, complex and ill-tested. I admit, I haven't given it a try recently but you can guess why I hate the very idea of approaching it without a ten-foot pole.
I've seen XFS screw a number of random files, ext3 mangled only files that were being written to, and my personal favourite is JFS. Even though I use JFS most of the time, the only screwup I witnessed was on a RAID without a write-intent bitmap.
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Despite the parent trying to be funny, NTFS does support shrinking. I've used it to shrink a full disk partition down a bit to install a Linux one on the side.
(Now queue 'no room left for Windows on the drive' jokes)
ReiserFS is still being used and maintained in-kernel. It's Stable, and it just works for you and for hundreds of thousands of others; so, what's the rush?
I'd wait for the next batch of next gen FS (BTRFS, Tux3) to show their stuff -- and perhaps take a look at getting involved. Daniel Phillips has recently sent out a call for help... Sounds like you have an itch -- go scratch it.
Performance may crawl to a standstill but ext3 with full journaling of data not just meta-data should make crash-recovery nearly bulletproof.
Another option is to reduce the number of crashes:
Make sure your software and hardware are stable and use a good, stable battery-backed power supply.
The latter is good advice for any system.
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I'm not sure if gparted can do it yet, but you can shrink and grow ext2/3 partitions at the command line using a combination of tools.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
He's concerned about "large files" because ext3 takes eons (10 to 20 seconds) to delete large (8GB/hr) files generated by recording HDTV. This used to be important on MythTV, because deletions were synchronous. So using ext2 in combination with HDTV on MythTV meant a 10 to 20 second "freeze" when manually deleting something, or missing 10-20 seconds of a new recording while an auto-expire deleted an old show.
In newer versions of MythTV, deletions are done by a separate thread, so there should be no concerns about using ext2/ext3.
ZFS isn't available on Linux.
ZFS is available on Linux, via Fuse. This gives a heavy performance penalty over a native implementation(*), but it would probably be fast enough for MythTV. However, ZFS is not shrinkable, so it doesn't meet the original poster's requirements.
(*)For a raidZ 3-disk array of WD "green" 750GB Sata drives (WD7500AACS-00ZJB0), I see 80MB/s sequential write, and 144MB/s sequential read for a native ZFS implementation on FreeBSD/amd64 7.0. For the same setup, I saw 25MB/s write and 95MB/s read from ZFS via fuse.
If something rock-solid is needed, one could do worse than continue to use ReiserFS3. (This is what I use.) It's feature-complete, and very stable. I have not had one mishap with it since I implemented it years ago.
But if you want something more bleeding-edge, one could try Reiser4 (development of which I think has stagnated) or btrfs, which seems to implement the main design considerations of Reiser4, but has jagged edges waiting to be cleaned up.
If something stable and under current maintenance is required, a conservative suggestion is of course Ext3.
XFS or JFS might be perfectly good solutions
One should never, ever use XFS on a non-UPS-protected system. It's a great filesystem, but if you don't get the time for a sync of the in-memory structures, you're screwed.
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What about ext3?
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