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On Sat, Feb 25, 2012 at 3:52 PM, Richard Yao <ryao@×××××××××××××.edu> wrote: |
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> ZFSOnLinux performance tuning is not a priority either, but there have |
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> been a few patches and the performance is good. btrfs might one day |
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> outperform ZFS in terms of single disk performance, assuming that it |
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> does not already, but I question the usefulness of single disk |
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> performance as a performance metric. |
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Why would btrfs be inferior to ZFS on multiple disks? I can't see how |
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its architecture would do any worse, and the planned features are |
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superior to ZFS (which isn't to say that ZFS can't improve either). |
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Beyond the licensing issues ZFS also does not support reshaping of |
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raid-z, which is the only n+1 redundancy solution it offers. Btrfs of |
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course does not yet support n+1 at all aside from some experimental |
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patches floating around, but it plans to support reshaping at some |
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point in time. Of course, there is no reason you couldn't implement |
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reshaping for ZFS, it just hasn't happened yet. Right now the |
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competition for me is with ext4+lvm+mdraid. While I really would like |
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to have COW soon, I doubt I'll implement anything that doesn't support |
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reshaping as mdraid+lvm does. |
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I do realize that you can add multiple raid-zs to a zpool, but that |
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isn't quite enough. If I have 4x1TB disks I'd like to be able to add |
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a single 1TB disk and end up with 5TB of space. I'd rather not have |
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to find 3 more 1TB hard drives to hold the data on while I redo my |
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raid and then try to somehow sell them again. |
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Rich |
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