ZFS raid write performance?

[Xin Li]

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On 6/22/15 01:14, Quartz wrote:
> What's sequential write performance like these days for ZFS
> raidzX? Someone suggested to me that I set up a single not-raid
> disk to act as a fast 'landing pad' for receiving files, then move
> them to the pool later in the background. Is that actually
> necessary? (Assume generic sata drives, 250mb-4gb sized files, and
> transfers are across a LAN using single unbonded GigE).

That sounds really weird recommendation IMHO.  Did "someone" explained
with the reasoning/benefit of that "landing pad"?

I don't have hardware for testing handy, but IIRC even with 10,000 RPM
hard drives, a single hard drive won't do much beyond 100MB/s (maybe
120MB/s max) for sequential 128kB blocks, so that "landing pad" would
probably not very helpful assuming you can saturate your GigE network
(and keep in mind that with a file system in place it's not a perfect
sequential operation; plus if there is something wrong with that hard
drive you will have to start over rather than just replacing the bad
drive).

Cheers,
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