5 ms·

I take you intended "modern" (eg. data checksumming, and maybe volume management)? It's hard not to qualify ext4 as "decent".

tjoff 9y ago
"Modern" would have been suitable a decade ago. The current state of filesystems on Linux is inexcusable.
- colejohnson66 9y ago
  If you’re gonna say something is out of date, at least say what could be better.
  - tjoff 9y ago
    That is fairly obvious isn't it? Copy on write and checksumming are two basics. And on top of CoW you can get snapshots (which in turn helps with backups, etc. etc.).
    - tscs37 9y ago
      Not everyone needs copy on write and checksumming, it doesn't make sense to waste CPU cycles on checksums when the use case doesn't require it. ext4 is a perfectly fine filesystem for most desktop users and a wide range of servers simply by not being ZFS. If you need CoW and checksumming, there is btrfs too, which is natively supported on Linux and IMO fine if you're only on a single disk or use md or LVM for RAID. It's quite amusing tbh when people think that a filesystem needs to do everything.
      - tjoff 9y ago
        Checksumming is free on todays CPUs, you could use your argument agains filesystem journaling as well. But for some reason you are not proposing using ext2? Why not? Why waste clock cycles on a journal when you might not need it? This truly is a non-issue but in very exceptional circumstances, and in such you don't use a general purpose filesystem anyway. Checksumming and snapshots etc. give substantial game-changing improvements to the whole system. More than a journaling filesystem ever did. They also provide means as to vastly simplify other tasks. Roll-back last system-wide update? Done. Backup consistency? Free and vastly simplified. I disagree, these are properties that are expected of any decent general purpose filesystem. If you fall into a niche that doesn't, fine, use one of the many alternatives. But this should be the default for all user-facing machines as well as servers.
        tscs37 9y ago
        Checksumming is rather not free on today's CPUs unless you use something like xxhash which operates close to RAM speed. Journaling is rather useful because especially consumer desktop computers tend to be mistreated and crash a lot. The physical journal in ext4 prevents the worst when stuff gets hairy. Additionally, it does not effectively delete data like ZFS (or rather, make it very very hard to access data) just because a bit was corrupted. I think a user will value their family pictures more than some random text file suddenly having another character somewhere, they will loose data with a checksumming FS on a normal machine. There is no second drive to pull a good copy of the data from. There is one. And you just killed the last picture of grandma. Congrats. >Why waste clock cycles on a journal when you might not need it? Journaling wastes mostly bandwidth and IO, not much CPU and clock cycles. >Roll-back last system-wide update? Done. Backup consistency? Free and vastly simplified. That is indeed something you can do with a CoW system but the tools to achieve this are in my experience not fully mature yet. The same tasks can also be achieved without snapshots at all, NixOS seems to be doing fine. >Backup consistency? Free and vastly simplified. Snapshots are not backups. If you pretend they are you will loose all your data. Snapshots are snapshots. Nothing more and nothing less. Not backups. >But this should be the default for all user-facing machines as well as servers. I've not stated they shouldn't be default, rather, that the end user does not necessarily need them. Though, ZFS is doing a rather poor job on all these tasks, especially disk management on ZFS is a hassle I wouldn't have a typical end user face. I think Bcache FS is a much cleaner and better design than ZFS, which is rather unflexible. But again, I don't see the immediate need for every end user machine to have a checksumming and CoW filesystem, people have been doing fine for years without them and I doubt there is chaos and fire everywhere as you seem to imply. It could be a little bit better but ext4 is a perfectly fine filesystem for production data. If you rely on checksumming and snapshots for your data safety, you're in for a bad time. Proper backups, not snapshots, will beat snapshots any day. Checksums make data inaccessible, a rather bad choice for a user machine. Whoops, I guess those family photos are totally unusuable because 1 bit has corrupted.
        heinrich5991 9y ago
        >>Backup consistency? Free and vastly simplified. >Snapshots are not backups. If you pretend they are you will loose all your data. The good thing about snapshots it that you can use them as a consistent base for your backup: If you naively copy files over from a running system, you'll get inconsistent data, but if you copy it over from a snapshot, it'll work without taking the system down.
    - wazoox 9y ago
      XFS has metadata checksumming, and CoW works (but still experimental) with recent kernels. And it generally runs circles around other filesystems, too.
    - colejohnson66 9y ago
      Doesn't copy on write ruin the ability to preallocate files?

tjoff 9y ago

"Modern" would have been suitable a decade ago. The current state of filesystems on Linux is inexcusable.

colejohnson66 9y ago
If you’re gonna say something is out of date, at least say what could be better.
- tjoff 9y ago
  That is fairly obvious isn't it? Copy on write and checksumming are two basics. And on top of CoW you can get snapshots (which in turn helps with backups, etc. etc.).
  - tscs37 9y ago
    Not everyone needs copy on write and checksumming, it doesn't make sense to waste CPU cycles on checksums when the use case doesn't require it. ext4 is a perfectly fine filesystem for most desktop users and a wide range of servers simply by not being ZFS. If you need CoW and checksumming, there is btrfs too, which is natively supported on Linux and IMO fine if you're only on a single disk or use md or LVM for RAID. It's quite amusing tbh when people think that a filesystem needs to do everything.
    - tjoff 9y ago
      Checksumming is free on todays CPUs, you could use your argument agains filesystem journaling as well. But for some reason you are not proposing using ext2? Why not? Why waste clock cycles on a journal when you might not need it? This truly is a non-issue but in very exceptional circumstances, and in such you don't use a general purpose filesystem anyway. Checksumming and snapshots etc. give substantial game-changing improvements to the whole system. More than a journaling filesystem ever did. They also provide means as to vastly simplify other tasks. Roll-back last system-wide update? Done. Backup consistency? Free and vastly simplified. I disagree, these are properties that are expected of any decent general purpose filesystem. If you fall into a niche that doesn't, fine, use one of the many alternatives. But this should be the default for all user-facing machines as well as servers.
      - tscs37 9y ago
        Checksumming is rather not free on today's CPUs unless you use something like xxhash which operates close to RAM speed. Journaling is rather useful because especially consumer desktop computers tend to be mistreated and crash a lot. The physical journal in ext4 prevents the worst when stuff gets hairy. Additionally, it does not effectively delete data like ZFS (or rather, make it very very hard to access data) just because a bit was corrupted. I think a user will value their family pictures more than some random text file suddenly having another character somewhere, they will loose data with a checksumming FS on a normal machine. There is no second drive to pull a good copy of the data from. There is one. And you just killed the last picture of grandma. Congrats. >Why waste clock cycles on a journal when you might not need it? Journaling wastes mostly bandwidth and IO, not much CPU and clock cycles. >Roll-back last system-wide update? Done. Backup consistency? Free and vastly simplified. That is indeed something you can do with a CoW system but the tools to achieve this are in my experience not fully mature yet. The same tasks can also be achieved without snapshots at all, NixOS seems to be doing fine. >Backup consistency? Free and vastly simplified. Snapshots are not backups. If you pretend they are you will loose all your data. Snapshots are snapshots. Nothing more and nothing less. Not backups. >But this should be the default for all user-facing machines as well as servers. I've not stated they shouldn't be default, rather, that the end user does not necessarily need them. Though, ZFS is doing a rather poor job on all these tasks, especially disk management on ZFS is a hassle I wouldn't have a typical end user face. I think Bcache FS is a much cleaner and better design than ZFS, which is rather unflexible. But again, I don't see the immediate need for every end user machine to have a checksumming and CoW filesystem, people have been doing fine for years without them and I doubt there is chaos and fire everywhere as you seem to imply. It could be a little bit better but ext4 is a perfectly fine filesystem for production data. If you rely on checksumming and snapshots for your data safety, you're in for a bad time. Proper backups, not snapshots, will beat snapshots any day. Checksums make data inaccessible, a rather bad choice for a user machine. Whoops, I guess those family photos are totally unusuable because 1 bit has corrupted.
        heinrich5991 9y ago
        >>Backup consistency? Free and vastly simplified. >Snapshots are not backups. If you pretend they are you will loose all your data. The good thing about snapshots it that you can use them as a consistent base for your backup: If you naively copy files over from a running system, you'll get inconsistent data, but if you copy it over from a snapshot, it'll work without taking the system down.
  - wazoox 9y ago
    XFS has metadata checksumming, and CoW works (but still experimental) with recent kernels. And it generally runs circles around other filesystems, too.
  - colejohnson66 9y ago
    Doesn't copy on write ruin the ability to preallocate files?