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Thread: Btrfs File-System Changes Published For Linux 3.13

  1. #11
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    Quote Originally Posted by jwilliams View Post
    Who said lack of a feature is a bug?

    Quite a few people would like to be able to choose a rollback snapshot at bootloader time, judging from the effort that has been put in to accomplish it. But so far it has failed to work well with btrfs.

    I'm not sure what you are talking about "do that after boot". You have to reboot to boot from a different snapshot.
    You said "You do not consider not "being fully implemented" an issue?", and issue is often an alias for bug.

    Nope, Snapper restores snapshots at runtime just fine. No rebooting needed.

  2. #12
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    Quote Originally Posted by jwilliams View Post
    You do not consider not "being fully implemented" an issue? And no 3-parity RAID like ZFS RAIDZ3.

    snapshots are not as flexible as on ZFS, there still seem to be various bugs reported for people making many snapshots, and it seems that most distro developers think that the btrfs snapshot capability is insufficient to implement a convenient system rollback feature at the bootloader stage

    But the biggest issue by far is the free space issue. Finding the free space is complicated, managing it is difficult even with the buggy quota functionality, and it is a major hassle to deal with a full btrfs filesystem.

    btrfs cannot equal the functionality of ZFS, nor the stability of ZFS, despite having been in development for 6 years now. (yes, I know ZFS has been in development since 2001, but ZFS had a stable release in 2005, and since most of the functionality in btrfs was already known and understood when btrfs development started since ZFS already pioneered it, we should expect btrfs development to be even faster than ZFS)
    OK, I'm nearly positive you're trolling at this point. Either that, or your just severely uninformed. You've offered no evidence to back up your wildly inaccurate claims.

    Why are snapshots not as flexible as ZFS?
    What issue is there with finding free space (besides you not understanding how to use the userspace tools)?
    Why should we expect btrfs developement to be faster than ZFS? (Hint: they don't have similar designs).

    Please provide some reasoned evidence, as you've yet to back up any of your claims.

  3. #13
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    Quote Originally Posted by GreatEmerald View Post
    Nope, Snapper restores snapshots at runtime just fine. No rebooting needed.
    False. You cannot "restore snapshots" without rebooting when certain changes have been made. For example, different kernel.

  4. #14
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    Quote Originally Posted by benmoran View Post
    OK, I'm nearly positive you're trolling at this point. Either that, or your just severely uninformed. You've offered no evidence to back up your wildly inaccurate claims.

    Why are snapshots not as flexible as ZFS?
    What issue is there with finding free space (besides you not understanding how to use the userspace tools)?
    Why should we expect btrfs developement to be faster than ZFS? (Hint: they don't have similar designs).

    Please provide some reasoned evidence, as you've yet to back up any of your claims.
    You asked me to elaborate, and I did. Now you insult me and demand "evidence". And after the insult, you write "Please". Do you think that excuses your rudeness? That was a rhetorical question, by the way. Don't answer.

    I am not interested in persuading you or writing a treatise with footnotes. I only elaborated because you asked. But now I am done with you. Read the btrfs email list if you want "evidence".

  5. #15
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    Quote Originally Posted by jwilliams View Post
    You asked me to elaborate, and I did. Now you insult me and demand "evidence". And after the insult, you write "Please". Do you think that excuses your rudeness? That was a rhetorical question, by the way. Don't answer.

    I am not interested in persuading you or writing a treatise with footnotes. I only elaborated because you asked. But now I am done with you. Read the btrfs email list if you want "evidence".
    Big claims require big evidence. All you've said is "This is bad, that is bad...", without actually providing any reasons.

  6. #16
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    Quote Originally Posted by jwilliams View Post
    False. You cannot "restore snapshots" without rebooting when certain changes have been made. For example, different kernel.
    Guess what, when you update your kernel, you have to reboot for it to take effect. There is no way around that (aside from kexec, but that's also not very reliable). And it's not the filesystem's job to deal with problems like that.

  7. #17
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    From my point of view biggest missing features are lz4 compression and proper raid.

    lz4 compression- I'm using some few-years-old systems and lzo effectively chokes the hardware but gives some additional space of course. Now, few weeks ago I've started using zswap with lz4 compression- and it's a big win even with old intel atom 1,6 GHz processor, with few percents of processor utilization. I guess that having it with btrfs would give huge boost for transfer speed of stored data with decent space savings. (zswap uses some compressed RAM space for swap and block devices are slower than ram, right?) It's like a huge technological breakthrough, I guess this kind of compression can be turned on on 95% of systems safely, by default, giving bigger storage space AND performance at the same time.

    raid thoughts- performance is quite inferior to md-raid, some of the reasons are from missing functionalities in btrfs raid implementation. For example no different data ordering options for raid10 (far, offset etc), no selection of chunk size (? I'm not sure), no odd drives number. As of raid5- I'm to scared to even try if this works for now, as far as I know it's rather incomplete. Luckily with btrfs I can convert my raid10 volumes to raid5 when time comes, on-the-fly :-)

  8. #18
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    Quote Originally Posted by elmystico View Post
    Luckily with btrfs I can convert my raid10 volumes to raid5 when time comes, on-the-fly :-)
    If you are "lucky", the time might come in another 6 years or so.

  9. #19
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    Quote Originally Posted by jwilliams View Post
    Unfortunately, btrfs is worse than ext4 in several ways, primarily reliability and free space issues, but also it is a poor choice for a swap file or for a large, random access file like that for a VM.
    Sure. It's also better in several ways.

    It's not quite ready yet, but let's wait another year and see how things stack up then.

  10. #20
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    Quote Originally Posted by jwilliams View Post
    I would not count on btrfs being "finalized" any time soon.

    The btrfs project was never very focused and directed. Now that Mason no longer works for Oracle, the project seems even more directionless than before. There are a number of people fixing bugs, but there always seem to be more bugs being discovered, and the important issues do not seem to get fixed or completed (qgroups, free space, parity RAID, snapshots, etc.)
    I think it also has to do with the fact that Oracle bought Sun and "owns" ZFS. Maybe they're focused on it more than on BTRFS? From one perspective it's good to have alternatives but then why spend resources when you have an advanced filesystem that does everything BTRFS was designed to do, especially when you're Oracle and are trying to squeeze every penny out.

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