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Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining() |
Date: |
Wed, 4 Apr 2018 16:06:00 +0800 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Wed, Apr 04, 2018 at 11:55:14AM +0530, Balamuruhan S wrote:
[...]
> > too. So still I'll put aside the "which one is better" question.
> >
> > For your use case, you can have a look on either of below way to
> > have a converged migration:
> >
> > - auto-converge: that's a migration capability that throttles CPU
> > usage of guests
>
> I used auto-converge option before hand and still it doesn't help
> for migration to complete
Have you digged about why? AFAIK auto-convergence will at last absort
merely the whole vcpu resource (99% of them maximum). Maybe you are
not with the best throttle values? Or do you think that could be a
auto-convergence bug too?
>
> >
> > - postcopy: that'll let you start the destination VM even without
> > transferring all the RAMs before hand
>
> I am seeing issue in postcopy migration between POWER8(16M) -> POWER9(1G)
> where the hugepage size is different. I am trying to enable it but host
> start
> address have to be aligned with 1G page size in ram_block_discard_range(),
> which I am debugging further to fix it.
I thought the huge page size needs to be matched on both side
currently for postcopy but I'm not sure. CC Dave (though I think
Dave's still on PTO).
--
Peter Xu
- [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), Balamuruhan S, 2018/04/01
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), Balamuruhan S, 2018/04/04
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(),
Peter Xu <=
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), Balamuruhan S, 2018/04/04
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), Dr. David Alan Gilbert, 2018/04/09
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), David Gibson, 2018/04/09
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), Dr. David Alan Gilbert, 2018/04/10
- Re: [Qemu-devel] [PATCH] migration: calculate expected_downtime with ram_bytes_remaining(), David Gibson, 2018/04/10