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Benchmarks Of ZFS-FUSE On Linux Against EXT4, Btrfs

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  • #46
    Originally posted by edogawaconan View Post
    Powering down computer with switch has risk of corrupting partially written data. It doesn't happen in zfs snapshot. How is it exactly same?
    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.

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    • #47
      FUSE Performance

      Originally posted by Michael View Post
      Typo, yeah, meant FUSE. Fixed. Thanks.
      ITS IN USERSPACE! If you asked for performance, your missing the point of FUSE. The point is to do things normally too unstable to support in kernel space. Doing this in userspace is of cores slow. As for getting this to near platter speed, that is impressive.

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      • #48
        ntfs-3g uses fuse too. maybe also interesting to compare.

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        • #49
          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.
          You went from "not a backup" to "only line of defense".
          Any database worth using should have no problem replaying transaction log.

          Also, creating zfs snapshot only takes one command and completes under a second. No need to do additional configuration and the snapshot can be sent incrementally to other machines. All this can be done without disrupting database process at all.

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          • #50
            Originally posted by edogawaconan View Post
            All this can be done without disrupting database process at all.
            As can transactional logs, so really I fail to see what this gains you in the real world and not just theoretically.

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            • #51
              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.

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              • #52
                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.

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                • #53
                  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

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                  • #54
                    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.

                    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.

                    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...

                    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.

                    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.

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                    • #55
                      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

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                      • #56
                        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.

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                        • #57
                          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

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                          • #58
                            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.

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                            • #59
                              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).

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                              • #60
                                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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