7 ms·

I've been running two very-lightly-used sets of pools on two old desktops for ... about a year and a half now actually and everything's gone swimmingly. Nor ha

I've been running two very-lightly-used sets of pools on two old desktops for ... about a year and a half now actually and everything's gone swimmingly. Nor have I read of anything bad happening to anyone that didn't involve not having backups. All in all, lots of people are running it, lots of people seem to be having almost entirely positive experiences with it, so it seems like it's very stable.

agumonkey 10y ago
Could you give machine specs ?
- barrkel 10y ago
  $ head -1 /proc/meminfo MemTotal: 4046880 kB $ grep model.name /proc/cpuinfo | head -1 model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz $ sudo zpool list NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT tank 36.2T 27.2T 9.09T - 10% 74% 1.00x ONLINE - That's 10x 4TB WD Red drives in raidz2 configuration. I've been running ZFS for the past 6 years, a little over 2 years on ZoL, and 4 years before that on Nexenta (Ubuntu userland with OpenSolaris kernel). I've had 5 HDD failures over the past few years, never lost any data. I've found ZoL to have less jitter when streaming video files in particular over SMB than the Solaris implementation did. ZoL is tighter on memory though. raidz2 isn't particularly fast for random I/O (since it acts like it has a single spindle), but I don't do much random I/O. It's mostly video and local backup cache. I'll be thinking about expanding my current setup soon enough. I'll probably be aiming for a raid10 setup for better random access, and of course the new system will have more RAM, and ECC.
  - agumonkey 10y ago
    Thanks. Beefier cpu than the beefier I got here, but RAM is a great hint that for personal needs ZFS can run on normal machines. Interesting that you had no issues without ECC in the first place. Some ZFS boards are pretty against trying ZFS without.
    - rincebrain 10y ago
      ZFS boards really encourage you to use ECC because one of the nominal features of ZFS, "end-to-end checksumming", is not quite as useful if you have a point between ends where it won't notice silent data corruption (e.g. a bad stick of non-ECC RAM). ZFS will notice, depending on _when_ the munging happened (if it was mangled after it got to RAM but before ZFS checksummed it, it obviously can't), but that's (primarily) why ZFS boards often tell you not to do that.
      - erkkie 10y ago
        Not only that, but I believe a bad checksum can also cause a cascade to "fix the data", causing further corruption.
        the_why_of_y 10y ago
        For that to happen, you would need a bad checksum and the corresponding data block to be corrupted in such a way that the corrupted data block checksums to the corrupted checksum. Given that the checksum is 256-bit, the scariest I'd call that is "possible in theory".
    - mioelnir 10y ago
      > Interesting that you had no issues without ECC in the first place. Some ZFS boards are pretty against trying ZFS without. ZFS without ECC is no better or worse than any other filesystem without ECC, in that silent data corruption is possible. It is for this reason just a lot worse than ZFS with ECC, introducing a fault condition normally not seen on ZFS. But that fault condition does not go away because you chose to skip ZFS due to no ECC. And you will get a lot of other problems on top that ZFS would have helped against, even without ECC. Lastly, you'll end up back in the horrible land of static partitioning schemes with questionable tooling. Why suffer through that if you do not have to?
    - Elhana 10y ago
      ZFS don't really need ECC that much, just FUD. Most likely someone got bitten by faulty RAM, got corrupted data, which stopped after getting ECC RAM. => "ZFS wants ECC" myth, but in reality you just need stable hardware. At the same time, if you are running like 30-40 TB pool, you probably want that ECC RAM, it will cost only small fraction of total storage box price and will save you from rebuilding a pool if shit happens.
  - coolspot 10y ago
    Wow! That is a lot of porn!
- doublerebel 10y ago
  ZFS can run on pretty low specs unless it's being pushed hard. I use a low-power AMD Sempron to keep things quiet. These specs are enough for all my backup and video streaming needs: $ head -1 /proc/meminfo MemTotal: 1967672 kB $ grep model.name /proc/cpuinfo | head -1 model name: AMD Sempron(tm) 145 Processor
  - gonzo 10y ago
    The in-development version of pfsense allows installs to ZFS, and I've installed onto a 2c atom with 2GB ram and a small SSD. But it's not as performant as UFS on the same hardware.
saurik 10y ago
> Nor have I read of anything bad happening to anyone that didn't involve not having backups. This should be true of any storage technology, no matter how unreliable (and thereby undermines the anecdote).
- devplusops 10y ago
  The trouble is it depends how you define 'backup'. E.g. if you are using zfs send/receive to do backups, and there's a bug in zfs send/receive.... Some people advise making sure you backup using different techniques/strategies/software, but in practice that gets quite difficult to manage, and you quickly end up going down a very deep rabbit hold on your quest for independent backup strategies. Consider this example: I'm aware of at least one instance where a faulty tape drive damaged the tapes used by that drive - in a a way that caused those tapes to damage other drives in the same way. The damage spread like a virus. Unless you have "blue" tapes, and "yellow" tapes, and "blue" drives, and "yellow drives", an issue like that won't be contained. But you do the combinatorics on all the kinds of issues like that which need to be addressed, and quickly you'll end up spending your whole life backing up data. Which will sort of solve the problem, because you won't have time to create any data which needs to be backed up.
tobias3 10y ago
As long as you don't backup with send/receive. ("Silently corrupted file in snapshots after send/receive" https://github.com/zfsonlinux/zfs/issues/4809 https://github.com/zfsonlinux/zfs/issues/4809)
- rincebrain 10y ago
  That's a bug in OpenZFS, to be fair, not ZoL-specific, though 0.6.5 not having a fix merged for a while is slightly surprising. Just grab https://github.com/zfsonlinux/zfs/pull/4833 https://github.com/zfsonlinux/zfs/pull/4833 and send/recv in safety. ;)

agumonkey 10y ago

Could you give machine specs ?

barrkel 10y ago
$ head -1 /proc/meminfo MemTotal: 4046880 kB $ grep model.name /proc/cpuinfo | head -1 model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz $ sudo zpool list NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT tank 36.2T 27.2T 9.09T - 10% 74% 1.00x ONLINE - That's 10x 4TB WD Red drives in raidz2 configuration. I've been running ZFS for the past 6 years, a little over 2 years on ZoL, and 4 years before that on Nexenta (Ubuntu userland with OpenSolaris kernel). I've had 5 HDD failures over the past few years, never lost any data. I've found ZoL to have less jitter when streaming video files in particular over SMB than the Solaris implementation did. ZoL is tighter on memory though. raidz2 isn't particularly fast for random I/O (since it acts like it has a single spindle), but I don't do much random I/O. It's mostly video and local backup cache. I'll be thinking about expanding my current setup soon enough. I'll probably be aiming for a raid10 setup for better random access, and of course the new system will have more RAM, and ECC.
- agumonkey 10y ago
  Thanks. Beefier cpu than the beefier I got here, but RAM is a great hint that for personal needs ZFS can run on normal machines. Interesting that you had no issues without ECC in the first place. Some ZFS boards are pretty against trying ZFS without.
  - rincebrain 10y ago
    ZFS boards really encourage you to use ECC because one of the nominal features of ZFS, "end-to-end checksumming", is not quite as useful if you have a point between ends where it won't notice silent data corruption (e.g. a bad stick of non-ECC RAM). ZFS will notice, depending on _when_ the munging happened (if it was mangled after it got to RAM but before ZFS checksummed it, it obviously can't), but that's (primarily) why ZFS boards often tell you not to do that.
    - erkkie 10y ago
      Not only that, but I believe a bad checksum can also cause a cascade to "fix the data", causing further corruption.
      - the_why_of_y 10y ago
        For that to happen, you would need a bad checksum and the corresponding data block to be corrupted in such a way that the corrupted data block checksums to the corrupted checksum. Given that the checksum is 256-bit, the scariest I'd call that is "possible in theory".
  - mioelnir 10y ago
    > Interesting that you had no issues without ECC in the first place. Some ZFS boards are pretty against trying ZFS without. ZFS without ECC is no better or worse than any other filesystem without ECC, in that silent data corruption is possible. It is for this reason just a lot worse than ZFS with ECC, introducing a fault condition normally not seen on ZFS. But that fault condition does not go away because you chose to skip ZFS due to no ECC. And you will get a lot of other problems on top that ZFS would have helped against, even without ECC. Lastly, you'll end up back in the horrible land of static partitioning schemes with questionable tooling. Why suffer through that if you do not have to?
  - Elhana 10y ago
    ZFS don't really need ECC that much, just FUD. Most likely someone got bitten by faulty RAM, got corrupted data, which stopped after getting ECC RAM. => "ZFS wants ECC" myth, but in reality you just need stable hardware. At the same time, if you are running like 30-40 TB pool, you probably want that ECC RAM, it will cost only small fraction of total storage box price and will save you from rebuilding a pool if shit happens.
- coolspot 10y ago
  Wow! That is a lot of porn!
doublerebel 10y ago
ZFS can run on pretty low specs unless it's being pushed hard. I use a low-power AMD Sempron to keep things quiet. These specs are enough for all my backup and video streaming needs: $ head -1 /proc/meminfo MemTotal: 1967672 kB $ grep model.name /proc/cpuinfo | head -1 model name: AMD Sempron(tm) 145 Processor
- gonzo 10y ago
  The in-development version of pfsense allows installs to ZFS, and I've installed onto a 2c atom with 2GB ram and a small SSD. But it's not as performant as UFS on the same hardware.

saurik 10y ago

> Nor have I read of anything bad happening to anyone that didn't involve not having backups. This should be true of any storage technology, no matter how unreliable (and thereby undermines the anecdote).

devplusops 10y ago
The trouble is it depends how you define 'backup'. E.g. if you are using zfs send/receive to do backups, and there's a bug in zfs send/receive.... Some people advise making sure you backup using different techniques/strategies/software, but in practice that gets quite difficult to manage, and you quickly end up going down a very deep rabbit hold on your quest for independent backup strategies. Consider this example: I'm aware of at least one instance where a faulty tape drive damaged the tapes used by that drive - in a a way that caused those tapes to damage other drives in the same way. The damage spread like a virus. Unless you have "blue" tapes, and "yellow" tapes, and "blue" drives, and "yellow drives", an issue like that won't be contained. But you do the combinatorics on all the kinds of issues like that which need to be addressed, and quickly you'll end up spending your whole life backing up data. Which will sort of solve the problem, because you won't have time to create any data which needs to be backed up.

tobias3 10y ago

As long as you don't backup with send/receive. ("Silently corrupted file in snapshots after send/receive" https://github.com/zfsonlinux/zfs/issues/4809 https://github.com/zfsonlinux/zfs/issues/4809)

rincebrain 10y ago
That's a bug in OpenZFS, to be fair, not ZoL-specific, though 0.6.5 not having a fix merged for a while is slightly surprising. Just grab https://github.com/zfsonlinux/zfs/pull/4833 https://github.com/zfsonlinux/zfs/pull/4833 and send/recv in safety. ;)