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Re: [Qemu-devel] Change in qemu 2.12 causes qemu-img convert to NBD to w
From: |
Richard W.M. Jones |
Subject: |
Re: [Qemu-devel] Change in qemu 2.12 causes qemu-img convert to NBD to write more data |
Date: |
Wed, 7 Nov 2018 14:36:28 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Another thing I tried was to change the NBD server (nbdkit) so that it
doesn't advertise zero support to the client:
$ nbdkit --filter=log --filter=nozero memory size=6G logfile=/tmp/log \
--run './qemu-img convert ./fedora-28.img -n $nbd'
$ grep '\.\.\.$' /tmp/log | sed 's/.*\([A-Z][a-z]*\).*/\1/' | uniq -c
2154 Write
Not surprisingly no zero commands are issued. The size of the write
commands is very uneven -- it appears to be send one command per block
of zeroes or data.
Nir: If we could get information from imageio about whether zeroing is
implemented efficiently or not by the backend, we could change
virt-v2v / nbdkit to advertise this back to qemu.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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- [Qemu-devel] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Richard W.M. Jones, 2018/11/07
- Re: [Qemu-devel] Change in qemu 2.12 causes qemu-img convert to NBD to write more data,
Richard W.M. Jones <=
- Re: [Qemu-devel] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Nir Soffer, 2018/11/07
- Re: [Qemu-devel] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Richard W.M. Jones, 2018/11/07
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Kevin Wolf, 2018/11/07
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Nir Soffer, 2018/11/07
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Nir Soffer, 2018/11/11
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Nir Soffer, 2018/11/15
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Kevin Wolf, 2018/11/16
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Nir Soffer, 2018/11/17
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Richard W.M. Jones, 2018/11/17
- Re: [Qemu-devel] [Qemu-block] Change in qemu 2.12 causes qemu-img convert to NBD to write more data, Nir Soffer, 2018/11/18