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From: Peter Lieven <pl@kamp.de>
To: Stefan Hajnoczi <stefanha@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Fam Zheng <famz@redhat.com>, Juan Quintela <quintela@redhat.com>,
	wency@cn.fujitsu.com, qemu block <qemu-block@nongnu.org>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: [Qemu-devel] block migration and MAX_IN_FLIGHT_IO
Date: Thu, 22 Feb 2018 12:13:50 +0100	[thread overview]
Message-ID: <c0d7b993-b3b8-a753-21f5-e2257de27caf@kamp.de> (raw)

Hi,


I stumbled across the MAX_INFLIGHT_IO field that was introduced in 2015 and was curious what was the reason

to choose 512MB as readahead? The question is that I found that the source VM gets very unresponsive I/O wise

while the initial 512MB are read and furthermore seems to stay unreasponsive if we choose a high migration speed

and have a fast storage on the destination VM.


In our environment I modified this value to 16MB which seems to work much smoother. I wonder if we should make

this a user configurable value or define a different rate limit for the block transfer in bulk stage at least?


Peter

             reply	other threads:[~2018-02-22 11:14 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-22 11:13 Peter Lieven [this message]
2018-03-05 11:45 ` [Qemu-devel] block migration and MAX_IN_FLIGHT_IO Stefan Hajnoczi
2018-03-05 14:37   ` Peter Lieven
2018-03-05 14:52     ` Dr. David Alan Gilbert
2018-03-06 16:07       ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2018-03-06 16:35         ` Peter Lieven
2018-03-07  7:55           ` Peter Lieven
2018-03-07  8:06             ` [Qemu-devel] block migration and dirty bitmap reset Peter Lieven
2018-03-08  1:28               ` Fam Zheng
2018-03-08  8:57                 ` Peter Lieven
2018-03-08  9:01                   ` Fam Zheng
2018-03-08 10:33                     ` Peter Lieven
2018-03-07  9:47             ` [Qemu-devel] [Qemu-block] block migration and MAX_IN_FLIGHT_IO Stefan Hajnoczi
2018-03-07 20:35               ` Peter Lieven
2018-03-06 16:14       ` [Qemu-devel] " Peter Lieven

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