4 ms·

What about ZFS?

rwaksmunski 5y ago
What about it? It does big storage really, really well.
jqpabc123 5y ago
Suspect as well --- for the same reason. System level data handling functionality is critical and needs to be rock solid. Complexity makes this more difficult to achieve. Not to say it's impossible, just increasingly more difficult.
- db48x 5y ago
  I disagree. I think that the traditional split between block devices and file systems is a premature optimization that ZFS fixes. And in practice ZFS is extraordinarily solid.
  - krageon 5y ago
    > And in practice ZFS is extraordinarily solid. As long as you never ever run into an edge case it's great, but then again the same goes for btrfs :)
    - db48x 5y ago
      Did you have anything specific in mind? Because otherwise that statement could apply to anything.
uniqueuid 5y ago
I have to second this - the rampant layering violation that is ZFS has in my experience been extremely robust. Maybe it's simply doing the "one coherent tool to manage large chunks of data and disks" thing well.
- creshal 5y ago
  "Do only one thing and do it well" is highly dependent on how you define "thing", yes. Is awk bad because you can't compose the internals of its built-in functions? Are vim and emacs bad because they have multiple modes of operation? Is bash violating the unix spirit by doing both the job of an interactive shell and a C API extensible scripting engine? I don't think so. ZFS, BTRFS, and advanced ext4 features like encryption are more arguments that layered block devices may have been a poor choice of abstraction.
ajross 5y ago
ZFS is a more mature and (maybe?) more performant solution to... the same wrong problem. The modern world doesn't want this stuff from its filesystems. It just doesn't. Modern flash devices are extremely reliably and outrageously fast, and they pervasively sit on high bandwidth internet connections which provide reliable backup for virtually every application imaginable. RAID and checksumming[1] just isn't used at the level of small/personal devices anywhere anymore, and really it never will be. And as you scale higher, single filesystems just don't cut it anyway. Cloud storage paradigms work on much larger bits, and worry about things like multi-site failover and atomicity. ZFS/btrfs has nothing to offer someone working on an S3-like service, or a globalized database, either. I mean, it's fine. Use it if you like it and you have an esoteric application that can leverage it (lots of hackers' personal networks tend to have toys like that). For that matter btrfs is fine too; my main data server at home is scripted around btrfs snapshots because they're easy. But really... fancy filesystems are just software in need of a home. Run ext4 or whatever and don't sweat it. [1] Non-encryption checksumming anyway. dm-verity doesn't work at the filesystem layer, nor should it.
- uniqueuid 5y ago
  Although I completely agree with your observations - sitting in a weird spot between very large and very small data, there are use cases where ZFS is extremely useful. I'm regularly working with datasets in the single to two digit TB range. They need to sit on disk because the university doesn't have 10GE. If I ran a regular raid and would encounter a disk or data error, I would have to re-create the data from tape archive or worse, lose it; and getting a replacement disk would surely take weeks. So instead, I've been running raidz pools for ~10 years and have never skipped a beat. I agree that this is not very typical, but it suits my needs perfectly.
- curt15 5y ago
  Isn't Lustre designed specifically for ZFS as its backing filesystem?
  - ajross 5y ago
    No, Lustre shipped on ext4 for years and years. Not an expert, but IIRC there aren't any core/major/whatever features in ZFS being leveraged in an irreplaceable way. Again, ZFS works fine, it's there (so is btrfs). Use it if it does something you like. It's just not really "worth" the level of complexity involved, and the window has long since closed for fancy filesystems to change any major paradigms of computation. This is dinosaur technology, basically.

What about ZFS?

What about it? It does big storage really, really well.

Suspect as well --- for the same reason. System level data handling functionality is critical and needs to be rock solid. Complexity makes this more difficult to achieve. Not to say it's impossible, just increasingly more difficult.

db48x 5y ago
I disagree. I think that the traditional split between block devices and file systems is a premature optimization that ZFS fixes. And in practice ZFS is extraordinarily solid.
- krageon 5y ago
  > And in practice ZFS is extraordinarily solid. As long as you never ever run into an edge case it's great, but then again the same goes for btrfs :)
  - db48x 5y ago
    Did you have anything specific in mind? Because otherwise that statement could apply to anything.

uniqueuid 5y ago

I have to second this - the rampant layering violation that is ZFS has in my experience been extremely robust. Maybe it's simply doing the "one coherent tool to manage large chunks of data and disks" thing well.

creshal 5y ago
"Do only one thing and do it well" is highly dependent on how you define "thing", yes. Is awk bad because you can't compose the internals of its built-in functions? Are vim and emacs bad because they have multiple modes of operation? Is bash violating the unix spirit by doing both the job of an interactive shell and a C API extensible scripting engine? I don't think so. ZFS, BTRFS, and advanced ext4 features like encryption are more arguments that layered block devices may have been a poor choice of abstraction.

ajross 5y ago

ZFS is a more mature and (maybe?) more performant solution to... the same wrong problem. The modern world doesn't want this stuff from its filesystems. It just doesn't. Modern flash devices are extremely reliably and outrageously fast, and they pervasively sit on high bandwidth internet connections which provide reliable backup for virtually every application imaginable. RAID and checksumming[1] just isn't used at the level of small/personal devices anywhere anymore, and really it never will be. And as you scale higher, single filesystems just don't cut it anyway. Cloud storage paradigms work on much larger bits, and worry about things like multi-site failover and atomicity. ZFS/btrfs has nothing to offer someone working on an S3-like service, or a globalized database, either. I mean, it's fine. Use it if you like it and you have an esoteric application that can leverage it (lots of hackers' personal networks tend to have toys like that). For that matter btrfs is fine too; my main data server at home is scripted around btrfs snapshots because they're easy. But really... fancy filesystems are just software in need of a home. Run ext4 or whatever and don't sweat it. [1] Non-encryption checksumming anyway. dm-verity doesn't work at the filesystem layer, nor should it.

uniqueuid 5y ago
Although I completely agree with your observations - sitting in a weird spot between very large and very small data, there are use cases where ZFS is extremely useful. I'm regularly working with datasets in the single to two digit TB range. They need to sit on disk because the university doesn't have 10GE. If I ran a regular raid and would encounter a disk or data error, I would have to re-create the data from tape archive or worse, lose it; and getting a replacement disk would surely take weeks. So instead, I've been running raidz pools for ~10 years and have never skipped a beat. I agree that this is not very typical, but it suits my needs perfectly.
curt15 5y ago
Isn't Lustre designed specifically for ZFS as its backing filesystem?
- ajross 5y ago
  No, Lustre shipped on ext4 for years and years. Not an expert, but IIRC there aren't any core/major/whatever features in ZFS being leveraged in an irreplaceable way. Again, ZFS works fine, it's there (so is btrfs). Use it if it does something you like. It's just not really "worth" the level of complexity involved, and the window has long since closed for fancy filesystems to change any major paradigms of computation. This is dinosaur technology, basically.