Re: *Really* bad I/O latency with md raid5+dm-crypt+lvm

[Arjan van de Ven]

On Mon, 12 Oct 2009 16:01:58 +0200
Christian Pernegger <pernegger@xxxxxxxxx> wrote:

> [Please keep me CCed as I'm not subscribed to LKML]
> 
> Summary: I was hoping to use a layered storage setup, namely lvm on
> dm-crypt on md raid5 for a new box I'm setting up, but that isn't
> looking so good since a single heavyish writer will monopolise any and
> all I/O on the "device". F. ex. while cp'ing a few GB of data from an
> external disk to the array it takes ~10sec to run ls and ~2min to
> start aptitude. Clueless attempts at a diagnosis below.


have you ran latencytop ?
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