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Thread: Benchmarks Of ZFS-FUSE On Linux Against EXT4, Btrfs

  1. #51
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    Quote Originally Posted by smitty3268 View Post
    As can transactional logs, so really I fail to see what this gains you in the real world and not just theoretically.
    By at all, I mean no delayed datafile writing, no additional write, and done in an instant.

  2. #52
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    Quote Originally Posted by edogawaconan View Post
    By at all, I mean no delayed datafile writing, no additional write, and done in an instant.
    And again, I ask: What's the point?

    I've got transactional logs being created every 10 minutes and getting backed up. What would this possibly gain me in real life and not just theoretically?

    Just because something CAN be done, doesn't mean it SHOULD be.

  3. #53
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    Quote Originally Posted by smitty3268 View Post
    And again, I ask: What's the point?

    I've got transactional logs being created every 10 minutes and getting backed up. What would this possibly gain me in real life and not just theoretically?

    Just because something CAN be done, doesn't mean it SHOULD be.
    - instaneous recovery (zfs rollback)
    - instaneous database cloning (useful when doing upgrade simulation, additionally, it doesn't use extra space until new data is written)
    - configuration-less backup
    - centralized, simple backup of everything, not just database (useful for all-in-one servers)

    Well, if those above don't matter to you, yes, probably there's no benefit in using zfs snapshot

  4. #54
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    Quote Originally Posted by edogawaconan View Post
    - instaneous recovery (zfs rollback)
    Well, after you fix the state by rolling back any open transactions. I'll give you that it's faster, though.

    Quote Originally Posted by edogawaconan View Post
    - instaneous database cloning (useful when doing upgrade simulation, additionally, it doesn't use extra space until new data is written)
    Now that does sound useful, although only in very limited scenarios - i.e. testing stuff on my local machine or during upgrades.

    Quote Originally Posted by edogawaconan View Post
    - configuration-less backup
    Well, you've got to configure a timed job somewhere, unless you're advocating backups on the fly whenever you happen to remember to want one...

    Quote Originally Posted by edogawaconan View Post
    - centralized, simple backup of everything, not just database (useful for all-in-one servers)
    Well, that's true, i suppose. But it's more of a crutch to allow you to do things poorly if you don't have the resources to properly back things up, if you ask me.

    Quote Originally Posted by edogawaconan View Post
    Well, if those above don't matter to you, yes, probably there's no benefit in using zfs snapshot
    There is actually 1 time when I used a VMWare snapshot (which is very similar, only it backs up the entire machine state with the disk, and i'm sure is much slower) and that was when going through a big database upgrade. It was nice to know that if everything went to ****, i could just touch a button and restore the whole machine back to working order without having to create a clean install, restoring all the data, etc.

    Very comforting to know that option existed, although I can't see using it for anything else.

  5. #55
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    Why does KQ Infotech get the press for this article? I thought they were just ripping off LLNL?

    http://www.phoronix.com/scan.php?pag...item&px=ODU1MA

  6. #56
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    Quote Originally Posted by locovaca View Post
    It is poor data management. Transaction logs shoulb be the last line of defense against failure, not the first. Timely, application specific backups should always be your first line of defense. ZFS snapshots, in this case, depend on the database engine's emergency recover processes as your only line of defense.
    very well put, for regular backups you use the tools provided by the database engine you use, online backups, incremental backups, after imagine, etc. etc. Using a snapshot for a regular backup and then relying on the transaction backout to work is simply bad practice and like Locovaca I would be fired in 12 hours if I would do that.

  7. #57
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    Since your SSD probably uses 4kb blocks, have you considered doing the benchmark for ZFS with an ashift of 12 (instead of 9 i.e. 0.5kb blocks)? For my damn WD drives this was a serious performance boost. http://www.solarismen.de/archives/2010/08/08.html

  8. #58
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    Quote Originally Posted by HisDudeness View Post
    Since your SSD probably uses 4kb blocks, have you considered doing the benchmark for ZFS with an ashift of 12 (instead of 9 i.e. 0.5kb blocks)? For my damn WD drives this was a serious performance boost. http://www.solarismen.de/archives/2010/08/08.html
    Very interesting article. This misaligment read can be becuase he was using disk slice/partition, not whole (recomended) disk. And partition could be possibly unaligned. I hope next zpool will include this parameter to be configured at creation, without needing to patch it.

    I will test if my zfs is working correctly on one of 2TB WD *EARS disk.

  9. #59
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    Quote Originally Posted by waucka View Post
    Snapshots only help you recover from "oops, I accidentally deleted a file", not "uh oh, the hard disk just failed".
    But snapshots also helps you backup file system (make snapshot, and then backup this snapshot to other file). It is just like switching off computer, and replicating it. For databases, and many others it is perfectly good strategy. Just copying data when file system is live and programs are constantly changing files would create inconsistencies. Atomic snapshot is prerequirement for good and correct backup. (it isn't replacement, but helps a lot).

  10. #60
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    Quote Originally Posted by kraftman View Post
    If this was Ext4 fault and if this happened in enterprise system (which didn't).



    Damn troll. Ext3, Ext4, XFS are great file systems. And no, it's not amazing, but it's something natural, because it's an Operating System which is present probably in every environment. What's the good choice in your opinion?
    Troll is an easy word! There is no doubt extX and XFS are great file systems. But they are so 10 years ago! Do they stack against ZFS or even against BTRFS in features? Where are consistent snapshots? where are the data checksums? Where is the built in compression and raid support?

    So, yes, they are great FS but not for today's storage requirements (checksums are not optional). So, calling the guy a troll is a trollish comment in my books.

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