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I've been using btrfs since about 2014 on CentOS7. I only use it with mirroring+compression. No snapshots. I mostly went with it for data scrubbing and compr

I've been using btrfs since about 2014 on CentOS7. I only use it with mirroring+compression. No snapshots. I mostly went with it for data scrubbing and compression. My experience has been mixed, but haven't had any data loss. There was a bug for a while regarding free space so occasionally the system would seem to be full but wasn't ....and it was a real pain to correct it. I now have a cron job that does a monthly btrfs balance along with a mount -oremount,clear_cache. I also run the latest kernels from http://elrepo.org http://elrepo.org instead of the CentOS7 kernels so that I get the latest patches.

Zardoz84 10y ago
Why the remount,clear_cache ? I'm doing a monthly balance before I got problems on a few servers.
- rrauenza 10y ago
  It's a little black magic -- didn't have time to completely research (this is a home NAS system.) I believe there was a bug in the clear space cache. This could cause the system to think it didn't have free blocks... you'd have to mount another device to create more space in order to rebalance and fix. Eventually I saw a bug fix report about a corruption in the cache... I never investigated to see if my current kernel has the fix.
gigatexal 10y ago
ZFS gets you all of that and raid and snapshots and has been tested time and time again. Why run BRTFS then?
- tylerjd 10y ago
  ZFS is not GPL? I dunno, I like feeling safe when I do kernel upgrades knowing even if for whatever reason my ZFS module doesn't compile/work under the new kernel, I won't be left without a root FS. I have been running BTRFS for 5 years with very little issues, and enjoy not having to compile a new dkms module with every kernel.
  - gigatexal 10y ago
    Ahhh yes that is the one ma in n point I missed. Can't argue with that. I've just never had issues upgrading as the zfs on Linux project us fantastic.
  - Zancarius 10y ago
    ZFS with DKMS is a disaster, at least in my experience. Honestly, I can't recommend ZoL unless you're running a distro with relatively stable kernel releases that don't change substantially or that happens to be supported by ZoL with binary packages. ZoL on Arch was... trying at times. It worked great, but my paranoia meant that I ended up adding the kernel to IgnorePkg to force manual kernel updates (mostly for my own memory). But then, it also meant having to build all of the ZFS packages (including SPL) tied to that specific version. This usually meant waiting until the AUR packages were updated as I figured that indicated someone else must have tested ZFS on that specific kernel version. I remembered thinking DKMS might solve the problem, but I ended up having to use recovery media just to get an environment to reinstall an older kernel and let DKMS do its thing after a botched update started provoking panics. I suspect a version mismatch based on the errors but never investigated it beyond fixing the problem and moving to the prebuilt modules. Things may have changed, but the Arch ZFS+DKMS packages were a bit flaky and required some manual modification just to boot (should've taken this as a warning!). Granted, it was my fault entirely for being a bit too enthusiastic with ZFS on Arch. To be honest, if I were to use it again, it would be on FreeBSD. Not Linux. I recognize it's fine for other people, but in my use case it wasn't.
    - lomnakkus 10y ago
      Your problem was running it on a distro the didn't support it. (As you acknowledge.) So far it's been running absolutely great for me on several Ubuntu installs.
      - Zancarius 10y ago
        Indeed. Arch is good for a few things, but sometimes stability isn't one of them when it comes to unsupported packages. ;) I'm not sure I'd be brave enough to run ZoL again, but given Ubuntu's FAR wider install base and availability of binary packages, it's the better option if you have to choose. My personal preference would be to stick with ZFS on FreeBSD. Performance is probably better.
- Dylan16807 10y ago
  BTRFS lets you make CoW copies of files. You can even retroactively merge the blocks that store identical files. BTRFS also makes it not a giant pain to remove a file from snapshots. ZFS does seem to work better overall, but I wouldn't call either filesystem great at this point in time.
- rrauenza 10y ago
  At the time of the system build, ZFS was user space only on CentOS7 if I recall.

Zardoz84 10y ago

Why the remount,clear_cache ? I'm doing a monthly balance before I got problems on a few servers.

rrauenza 10y ago
It's a little black magic -- didn't have time to completely research (this is a home NAS system.) I believe there was a bug in the clear space cache. This could cause the system to think it didn't have free blocks... you'd have to mount another device to create more space in order to rebalance and fix. Eventually I saw a bug fix report about a corruption in the cache... I never investigated to see if my current kernel has the fix.

gigatexal 10y ago

ZFS gets you all of that and raid and snapshots and has been tested time and time again. Why run BRTFS then?

tylerjd 10y ago
ZFS is not GPL? I dunno, I like feeling safe when I do kernel upgrades knowing even if for whatever reason my ZFS module doesn't compile/work under the new kernel, I won't be left without a root FS. I have been running BTRFS for 5 years with very little issues, and enjoy not having to compile a new dkms module with every kernel.
- gigatexal 10y ago
  Ahhh yes that is the one ma in n point I missed. Can't argue with that. I've just never had issues upgrading as the zfs on Linux project us fantastic.
- Zancarius 10y ago
  ZFS with DKMS is a disaster, at least in my experience. Honestly, I can't recommend ZoL unless you're running a distro with relatively stable kernel releases that don't change substantially or that happens to be supported by ZoL with binary packages. ZoL on Arch was... trying at times. It worked great, but my paranoia meant that I ended up adding the kernel to IgnorePkg to force manual kernel updates (mostly for my own memory). But then, it also meant having to build all of the ZFS packages (including SPL) tied to that specific version. This usually meant waiting until the AUR packages were updated as I figured that indicated someone else must have tested ZFS on that specific kernel version. I remembered thinking DKMS might solve the problem, but I ended up having to use recovery media just to get an environment to reinstall an older kernel and let DKMS do its thing after a botched update started provoking panics. I suspect a version mismatch based on the errors but never investigated it beyond fixing the problem and moving to the prebuilt modules. Things may have changed, but the Arch ZFS+DKMS packages were a bit flaky and required some manual modification just to boot (should've taken this as a warning!). Granted, it was my fault entirely for being a bit too enthusiastic with ZFS on Arch. To be honest, if I were to use it again, it would be on FreeBSD. Not Linux. I recognize it's fine for other people, but in my use case it wasn't.
  - lomnakkus 10y ago
    Your problem was running it on a distro the didn't support it. (As you acknowledge.) So far it's been running absolutely great for me on several Ubuntu installs.
    - Zancarius 10y ago
      Indeed. Arch is good for a few things, but sometimes stability isn't one of them when it comes to unsupported packages. ;) I'm not sure I'd be brave enough to run ZoL again, but given Ubuntu's FAR wider install base and availability of binary packages, it's the better option if you have to choose. My personal preference would be to stick with ZFS on FreeBSD. Performance is probably better.
Dylan16807 10y ago
BTRFS lets you make CoW copies of files. You can even retroactively merge the blocks that store identical files. BTRFS also makes it not a giant pain to remove a file from snapshots. ZFS does seem to work better overall, but I wouldn't call either filesystem great at this point in time.
rrauenza 10y ago
At the time of the system build, ZFS was user space only on CentOS7 if I recall.