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List:       linux-390
Subject:    Re: dasdfmt - why are you so darn slow?
From:       Rob van der Heij <rvdheij () gmail ! com>
Date:       2012-11-09 23:06:05
Message-ID: CAJCc=kh2jO0Dke8g5hRJ9+CA4odr3tGqQxcS9KOOxUh3MbDo4g () mail ! gmail ! com
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On 9 November 2012 23:52, Marcy Cortes <Marcy.D.Cortes@wellsfargo.com> wrote:
> Ok, no shortage of spares here.   So I tried it.   Not good.
>
> dasdfmt of 10000 cyl - non PPRC non XRC    - 1:55
> ICKDSF of 10000 cyl - non PPRC non XRC   -  1:13
> LXFMT of 10000 cyl - non PPRC  non XRC - 2:10
>
>
> dasdfmt of 10000 cyl - PPRC, XRC'd   - 5:00
> ICKDSF of 10000 cyl - PPRC, XRC'd - 1:29
> LXFMT of 10000 cyl - PPRC, XRC'd - 5:15
>
> So, actually worse than dasdfmt.

That's 15 seconds more for 150,000 tracks. That 0.1 ms per I/O might
be when they don't do short writes and transfer zeroes to the disk...
Think at 4 Gb/s the 50KB per track would be around 0.1ms (but it's too
late for math here now).

Rob

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