2011-09-29 17:15, Zaeem Arshad ?????:

On Thu, Sep 29, 2011 at 11:33 AM, Garrett D'Amore <garrett.dam...@gmail.com <mailto:garrett.dam...@gmail.com>> wrote:

    I think he means, resilver faster.

    SSDs can be driven harder, and have more IOPs so we can hit them
    harder with less impact on the overall performance.  The reason we
    throttle at all is to avoid saturating the bandwidth of the drive
    with resilver which would prevent regular operations from making
    progress.  Generally I believe resilver operations are not
    "bandwidth bound" in the sense of pure throughput, but are IOPs
    bound.  As SSDs have no seek time, they can handle a lot more of
    these little operations than a regular hard disk.

     - Garrett

What's the throttling rate if I may call it that?

IIRC about 7MBps, and I guess it is hardcoded since the value
is so well known as to have been reported several times.

I think another rationale for SSD throttling was with L2ARC tasks -
to reduce probable effects of write overdriving in SSD hardwares
(less efficient and more wear on SSD cells).


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