Messages in this thread | | | Date | Tue, 11 Dec 2012 09:56:45 +0100 | From | Lars Marowsky-Bree <> | Subject | Re: [dm-devel] [PATCH 0/3] add resync speed control for dm-raid1 |
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On 2012-12-10T13:21:23, NeilBrown <neilb@suse.de> wrote:
> The problem with this approach is that it slows down resync even when there > is no other IO happening. > If that is deemed to be acceptable, then the patch set seems fine, though I > would probably make the default a lot higher so as not to change current > default behaviour for anyone.
I agree to the latter part.
The difficulty is that our primary use case here is preventing IO starvation while cluster raid is resyncing; and we don't know the IO load on other nodes, or what other LVs might inflict on the same backend store / PV. Hence, a static limit probably is the easiest way to start.
I agree that a more dynamic approach would be desirable, but that appears to be very complex to get right.
Thanks, Lars
-- Architect Storage/HA SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 21284 (AG Nürnberg) "Experience is the name everyone gives to their mistakes." -- Oscar Wilde
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