Messages in this thread | | | Date | Mon, 16 Feb 2004 13:17:09 +0100 | From | Heinz Mauelshagen <> | Subject | Re: dm core patches |
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On Fri, Feb 13, 2004 at 03:39:36PM +0000, Joe Thornber wrote: > On Fri, Feb 13, 2004 at 04:12:14PM +0100, Lars Marowsky-Bree wrote: > > On 2004-02-12T20:13:40, > > Joe Thornber <thornber@redhat.com> said: > > > > > I think the main concern now is over the testing of paths. Sending an > > > io down an inactive path can be very expensive for some hardware > > > configurations. So I'm considering changing a couple of things: > > > > > > - Only ever send io to 1 priority group at a time (even test ios). > > > To test the lower priority groups we'd have to periodically switch to > > > them and use them for a bit for both test io and proper io. > > > > You are missing the obvious answer: > > > > - Periodically checking paths is a user-space issue and doesn't belong > > into the kernel. User-space gets to handle this policy. > > Yes, that is obvious, I had wanted to do failback automatically. But > pushing it to userland does allow people to write hardware specific > tests. I'll try it and see what people think.
Right, such policy belongs to userpsace it seems.
The reason why I put it into the multipath target is to cover the case, where all paths are inoperational, the system is OOM _and_ the only chance to recover from that is the hope to unfail a path in order to release memory preasure.
'Sorry, userspace test handler can't run, your enterprise server is a pile of sh..' is not acceptable in case there's a path we could unfail IMO.
Regards, Heinz -- The LVM Guy --
> > Thanks, > > - Joe > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
*** Software bugs are stupid. Nevertheless it needs not so stupid people to solve them ***
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Heinz Mauelshagen Red Hat, Inc. Consulting Development Engineer Am Sonnenhang 11 56242 Marienrachdorf Germany Mauelshagen@RedHat.com +49 2626 141200 FAX 924446 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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