IDE -- mount partitions for better performance
freebsd at edvax.de
Tue Mar 15 22:22:55 UTC 2011
On Tue, 15 Mar 2011 17:07:20 -0500, Adam Vande More <amvandemore at gmail.com> wrote:
> Your statement about master being faster than a slave is simply not true for
> almost every scenario when using devices with same capabilites. All
> master/slave really controls is enumeration, and shouldn't effect
> performance in and of itself. Other variables can effect that of course,
> like using a slower device as an ATA Device-1 with a faster Device-0. Even
> that example isn't ubiquitous as many, maybe most controllers are able to
> support mixed devices each in their fastest mode.
My statement originates back from individual experience
in settings where disks with different capabilities (esp.
very old + very new disk), as well as disk drive and an
optical drive with limited speed.
> The whole IDE device contention really isn't much of a bottle neck in this
> scenario. It's only a big factor when there's *a lot* of simultaneous IO
> going to both, say dumping one disk to another.
That's true: When copying (or moving) data from one disk
to the other master->master seems to be faster than
master->slave (same line), if I remember correctly.
> The highest preforming setup in something like this is likely to be
> something along the lines of a 4-way /boot gmirror, and a 4-way gstripe with
> a smaller stripe size eg 32k across the remaining usable space. If you
> aggregate your disk IO in this manner, IDE channel contention shouldn't be
> much of a bottleneck.
A good advice, I haven't thought of that (never tried, but
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
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