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Comment by bayindirh

4 days ago

> Most Linux distros still use ext4 by default, which is 19 years old, but ext4 is little more than a series of extensions on top of ext2, which is the same age as NTFS.

However, ext4 and XFS are much more simpler and performant than BTRFS & ZFS as root drives on personal systems and small servers.

I personally won't use either on a single disk system as root FS, regardless of how fast my storage subsystem is.

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bayindirh

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ryao  4 days ago

ZFS will outscale ext4 in parallel workloads with ease. XFS will often scale better than ext4, but if you use L2ARC and SLOG devices, it is no contest. On top of that, you can use compression for an additional boost.

You might also find ZFS outperforms both of them in read workloads on single disks where ARC minimizes cold cache effects. When I began using ZFS for my rootfs, I noticed my desktop environment became more responsive and I attributed that to ARC.

  • jeltz  4 days ago

    Not on most database workloads. There zfs does not scale very well.

    • ryao  4 days ago

      Percona and many others who benchmarked this properly would disagree with you. Percona found that ext4 and ZFS performed similarly when given identical hardware (with proper tuning of ZFS):

      https://www.percona.com/blog/mysql-zfs-performance-update/

      In this older comparison where they did not initially tune ZFS properly for the database, they found XFS to perform better, only for ZFS to outperform it when tuning was done and a L2ARC was added:

      https://www.percona.com/blog/about-zfs-performance/

      This is roughly what others find when they take the time to do proper tuning and benchmarks. ZFS outscales both ext4 and XFS, since it is a multiple block device filesystem that supports tiered storage while ext4 and XFS are single block device filesystems (with the exception of supporting journals on external drives). They need other things to provide them with scaling to multiple block devices and there is no block device level substitute for supporting tiered storage at the filesystem level.

      That said, ZFS has a killer feature that ext4 and XFS do not have, which is low cost replication. You can snapshot and send/recv without affecting system performance very much, so even in situations where ZFS is not at the top in every benchmark such as being on equal hardware, it still wins, since the performance penalty of database backups on ext4 and XFS is huge.

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  • bayindirh  4 days ago

    No doubt. I want to reiterate my point. Citing myself:

    > "I personally won't use either on a single disk system as root FS, regardless of how fast my storage subsystem is." (emphasis mine)

    We are no strangers to filesystems. I personally benchmarked a ZFS7320 extensively, writing a characterization report, plus we have a ZFS7420 for a very long time, complete with separate log SSDs for read and write on every box.

    However, ZFS is not saturation proof, plus is nowhere near a Lustre cluster performance wise, when scaled.

    What kills ZFS and BTRFS on desktop systems are write performance, esp. on heavy workloads like system updates. If I need a desktop server (performance-wise), I'd configure it accordingly and use these, but I'd never use BTRFS or ZFS on a single root disk due to their overhead, to reiterate myself thrice.