From: Paolo Bonzini <pbonzini@redhat.com>
To: "Denis V. Lunev" <den@openvz.org>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>,
Raushaniya Maksudova <rmaksudova@virtuozzo.com>
Subject: Re: [Qemu-devel] [PATCH RFC 0/5] disk deadlines
Date: Tue, 8 Sep 2015 11:43:53 +0200 [thread overview]
Message-ID: <55EEADD9.6010008@redhat.com> (raw)
In-Reply-To: <55EEAD4B.6090609@openvz.org>
On 08/09/2015 11:41, Denis V. Lunev wrote:
> This solution is far not perfect as there is a race window for
> request complete anyway. Though the amount of failures is
> reduced by 2-3 orders of magnitude.
>
> The behavior is similar not for soft mounts, which could
> corrupt the data but to hard mounts which are default AFAIR.
> It will not corrupt the data and should patiently wait
> request complete.
>
> Without the disk the guest is not able to serve any request and
> thus keeping it running does not make serious sense.
>
> This approach is used by Odin in production for years and
> we were able to seriously reduce the amount of end-user
> reclamations. We were unable to invent any reasonable
> solution without guest modification/timeouts tuning.
>
> Anyway, this code is off by default, storage agnostic, separated.
> Yes, we will be able to maintain it for us out-of-tree, but...
I'm not saying the patches are unacceptable, not at all. It just needs
a bit of documentation to understand the tradeoffs. I admit I have not
even started reading the code.
Your experience is very valuable, and it's great that you are
contributing it to QEMU and KVM!
Paolo
next prev parent reply other threads:[~2015-09-08 9:44 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-08 8:00 [Qemu-devel] [PATCH RFC 0/5] disk deadlines Denis V. Lunev
2015-09-08 8:00 ` [Qemu-devel] [PATCH 1/5] add QEMU style defines for __sync_add_and_fetch Denis V. Lunev
2015-09-10 8:19 ` Stefan Hajnoczi
2015-09-08 8:00 ` [Qemu-devel] [PATCH 2/5] disk_deadlines: add request to resume Virtual Machine Denis V. Lunev
2015-09-10 8:51 ` Stefan Hajnoczi
2015-09-10 19:18 ` Denis V. Lunev
2015-09-14 16:46 ` Stefan Hajnoczi
2015-09-08 8:00 ` [Qemu-devel] [PATCH 3/5] disk_deadlines: add disk-deadlines option per drive Denis V. Lunev
2015-09-10 9:05 ` Stefan Hajnoczi
2015-09-08 8:00 ` [Qemu-devel] [PATCH 4/5] disk_deadlines: add control of requests time expiration Denis V. Lunev
2015-09-08 9:35 ` Fam Zheng
2015-09-08 9:42 ` Denis V. Lunev
2015-09-08 11:06 ` Kevin Wolf
2015-09-08 11:27 ` Denis V. Lunev
2015-09-08 13:05 ` Kevin Wolf
2015-09-08 14:23 ` Denis V. Lunev
2015-09-08 14:48 ` Kevin Wolf
2015-09-10 10:27 ` Stefan Hajnoczi
2015-09-10 11:39 ` Kevin Wolf
2015-09-14 16:53 ` Stefan Hajnoczi
2015-09-25 12:34 ` Dr. David Alan Gilbert
2015-09-28 12:42 ` Stefan Hajnoczi
2015-09-28 13:55 ` Dr. David Alan Gilbert
2015-09-08 8:00 ` [Qemu-devel] [PATCH 5/5] disk_deadlines: add info disk-deadlines option Denis V. Lunev
2015-09-08 16:20 ` Eric Blake
2015-09-08 16:26 ` Eric Blake
2015-09-10 18:53 ` Denis V. Lunev
2015-09-10 19:13 ` Denis V. Lunev
2015-09-08 8:58 ` [Qemu-devel] [PATCH RFC 0/5] disk deadlines Vasiliy Tolstov
2015-09-08 9:20 ` Fam Zheng
2015-09-08 10:11 ` Kevin Wolf
2015-09-08 10:13 ` Denis V. Lunev
2015-09-08 10:20 ` Fam Zheng
2015-09-08 10:46 ` Denis V. Lunev
2015-09-08 10:49 ` Kevin Wolf
2015-09-08 13:20 ` Fam Zheng
2015-09-08 9:33 ` Paolo Bonzini
2015-09-08 9:41 ` Denis V. Lunev
2015-09-08 9:43 ` Paolo Bonzini [this message]
2015-09-08 10:37 ` Andrey Korolyov
2015-09-08 10:50 ` Denis V. Lunev
2015-09-08 10:07 ` Kevin Wolf
2015-09-08 10:08 ` Denis V. Lunev
2015-09-08 10:22 ` Stefan Hajnoczi
2015-09-08 10:26 ` Paolo Bonzini
2015-09-08 10:36 ` Denis V. Lunev
2015-09-08 19:11 ` John Snow
2015-09-10 19:29 ` [Qemu-devel] Summary: " Denis V. Lunev
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