* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
@ 2010-10-14 9:25 ` Stefan Hajnoczi
2010-10-14 9:41 ` Ildar
` (7 subsequent siblings)
8 siblings, 0 replies; 12+ messages in thread
From: Stefan Hajnoczi @ 2010-10-14 9:25 UTC (permalink / raw)
To: qemu-devel
It is possible to chain backing files. As a workaround you could do the
following:
$ qemu-img create -f qcow2 -b 2.img 4.img # from now on don't modify 2.img, instead use 4.img
$ qemu-img create -f qcow2 -b 2.img 3.img # here is the 3.img you tried to create with qemu-convert
Images 1.img and 2.img should never be modified, they are immutable
snapshots.
Images 3.img and 4.img can be modified and will contain only changes
against 2.img.
Perhaps qemu-img needs a command to drop data that is duplicated in the
base image. This could be a new flag to commit: qemu-img commit --dedup
3.img.
--
"qemu-img convert -O qcow2 -o backing_file" makes huge images
https://bugs.launchpad.net/bugs/660366
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
Status in QEMU: New
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as expected). I.e. all data is put into the resulting image: both from source image and "backing" image.
Expected behavior is to put only data that is not present in backing_file.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
2010-10-14 9:25 ` [Qemu-devel] [Bug 660366] " Stefan Hajnoczi
@ 2010-10-14 9:41 ` Ildar
2010-10-14 10:56 ` Stefan Hajnoczi
` (6 subsequent siblings)
8 siblings, 0 replies; 12+ messages in thread
From: Ildar @ 2010-10-14 9:41 UTC (permalink / raw)
To: qemu-devel
Do you confirm this as a bug?
--
"qemu-img convert -O qcow2 -o backing_file" makes huge images
https://bugs.launchpad.net/bugs/660366
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
Status in QEMU: New
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as expected). I.e. all data is put into the resulting image: both from source image and "backing" image.
Expected behavior is to put only data that is not present in backing_file.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
2010-10-14 9:25 ` [Qemu-devel] [Bug 660366] " Stefan Hajnoczi
2010-10-14 9:41 ` Ildar
@ 2010-10-14 10:56 ` Stefan Hajnoczi
2010-10-14 12:26 ` Anthony Liguori
` (5 subsequent siblings)
8 siblings, 0 replies; 12+ messages in thread
From: Stefan Hajnoczi @ 2010-10-14 10:56 UTC (permalink / raw)
To: qemu-devel
Sorry I'm not a frequent Launchpad user and will leave it up to someone
more familiar to decide which status to place it in.
--
"qemu-img convert -O qcow2 -o backing_file" makes huge images
https://bugs.launchpad.net/bugs/660366
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
Status in QEMU: New
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as expected). I.e. all data is put into the resulting image: both from source image and "backing" image.
Expected behavior is to put only data that is not present in backing_file.
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
` (2 preceding siblings ...)
2010-10-14 10:56 ` Stefan Hajnoczi
@ 2010-10-14 12:26 ` Anthony Liguori
2010-10-14 12:51 ` Stefan Hajnoczi
2013-05-23 7:56 ` Ildar
` (4 subsequent siblings)
8 siblings, 1 reply; 12+ messages in thread
From: Anthony Liguori @ 2010-10-14 12:26 UTC (permalink / raw)
To: qemu-devel
** Changed in: qemu
Importance: Undecided => Wishlist
** Changed in: qemu
Status: New => Confirmed
--
"qemu-img convert -O qcow2 -o backing_file" makes huge images
https://bugs.launchpad.net/bugs/660366
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
Status in QEMU: Confirmed
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as expected). I.e. all data is put into the resulting image: both from source image and "backing" image.
Expected behavior is to put only data that is not present in backing_file.
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 12:26 ` Anthony Liguori
@ 2010-10-14 12:51 ` Stefan Hajnoczi
2010-10-14 12:59 ` Anthony Liguori
0 siblings, 1 reply; 12+ messages in thread
From: Stefan Hajnoczi @ 2010-10-14 12:51 UTC (permalink / raw)
To: Anthony Liguori; +Cc: Bug 660366, qemu-devel
On Thu, Oct 14, 2010 at 1:26 PM, Anthony Liguori <anthony@codemonkey.ws> wrote:
> ** Changed in: qemu
> Importance: Undecided => Wishlist
>
> ** Changed in: qemu
> Status: New => Confirmed
Thanks for doing this Anthony. Can I set the status myself next time
or do we have rules on who handles bugs?
Stefan
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 12:51 ` Stefan Hajnoczi
@ 2010-10-14 12:59 ` Anthony Liguori
0 siblings, 0 replies; 12+ messages in thread
From: Anthony Liguori @ 2010-10-14 12:59 UTC (permalink / raw)
To: Stefan Hajnoczi; +Cc: Bug 660366, qemu-devel
On 10/14/2010 07:51 AM, Stefan Hajnoczi wrote:
> On Thu, Oct 14, 2010 at 1:26 PM, Anthony Liguori<anthony@codemonkey.ws> wrote:
>
>> ** Changed in: qemu
>> Importance: Undecided => Wishlist
>>
>> ** Changed in: qemu
>> Status: New => Confirmed
>>
> Thanks for doing this Anthony. Can I set the status myself next time
> or do we have rules on who handles bugs?
>
I'm pretty sure anyone can do it. If not, I'm certainly willing to give
people extra rights on the project if they want to help with bug triage.
Regards,
Anthony Liguori
> Stefan
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
` (3 preceding siblings ...)
2010-10-14 12:26 ` Anthony Liguori
@ 2013-05-23 7:56 ` Ildar
2013-05-23 8:08 ` Ildar
` (3 subsequent siblings)
8 siblings, 0 replies; 12+ messages in thread
From: Ildar @ 2013-05-23 7:56 UTC (permalink / raw)
To: qemu-devel
I guess the problem is solved already.
qemu-img version 1.4.0
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/660366
Title:
"qemu-img convert -O qcow2 -o backing_file" makes huge images
Status in QEMU:
Confirmed
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as
expected). I.e. all data is put into the resulting image: both from
source image and "backing" image.
Expected behavior is to put only data that is not present in
backing_file.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/660366/+subscriptions
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
` (4 preceding siblings ...)
2013-05-23 7:56 ` Ildar
@ 2013-05-23 8:08 ` Ildar
2015-08-10 12:37 ` sakishrist
` (2 subsequent siblings)
8 siblings, 0 replies; 12+ messages in thread
From: Ildar @ 2013-05-23 8:08 UTC (permalink / raw)
To: qemu-devel
** Changed in: qemu
Status: Confirmed => Fix Released
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/660366
Title:
"qemu-img convert -O qcow2 -o backing_file" makes huge images
Status in QEMU:
Fix Released
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as
expected). I.e. all data is put into the resulting image: both from
source image and "backing" image.
Expected behavior is to put only data that is not present in
backing_file.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/660366/+subscriptions
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
` (5 preceding siblings ...)
2013-05-23 8:08 ` Ildar
@ 2015-08-10 12:37 ` sakishrist
2015-08-11 9:42 ` Kevin Wolf
2015-08-11 10:08 ` sakishrist
8 siblings, 0 replies; 12+ messages in thread
From: sakishrist @ 2015-08-10 12:37 UTC (permalink / raw)
To: qemu-devel
Is this reintroduced? I am on version 2.3.0
$ dd if=/dev/urandom of=disk bs=1M count=1024
$ qemu-img convert -f raw -O qcow2 disk disk.qcow
$ qemu-img convert -f raw -O qcow2 -o backing_file=disk.qcow disk
disk1.qcow
$ ls -l
total 3146388
-rw-r--r-- 1 sakis sakis 1073741824 10 авг 15,29 disk
-rw-r--r-- 1 sakis sakis 1074135040 10 авг 15,30 disk.qcow
-rw-r--r-- 1 sakis sakis 1074135040 10 авг 15,31 disk1.qcow
All the data is copied again.
$ qemu-img info disk1.qcow
image: disk1.qcow
file format: qcow2
virtual size: 1.0G (1073741824 bytes)
disk size: 1.0G
cluster_size: 65536
*backing file: disk.qcow*
Format specific information:
compat: 1.1
lazy refcounts: false
refcount bits: 16
corrupt: false
Qemu-img works as expected though.
$ qemu-img create -f qcow2 -o backing_file=disk1.qcow disk2.qcow
$ ls -l
total 3146584
-rw-r--r-- 1 sakis sakis 1073741824 10 авг 15,29 disk
-rw-r--r-- 1 sakis sakis 1074135040 10 авг 15,30 disk.qcow
-rw-r--r-- 1 sakis sakis 1074135040 10 авг 15,31 disk1.qcow
-rw-r--r-- 1 sakis sakis 197120 10 авг 15,33 disk2.qcow
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/660366
Title:
"qemu-img convert -O qcow2 -o backing_file" makes huge images
Status in QEMU:
Fix Released
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as
expected). I.e. all data is put into the resulting image: both from
source image and "backing" image.
Expected behavior is to put only data that is not present in
backing_file.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/660366/+subscriptions
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
` (6 preceding siblings ...)
2015-08-10 12:37 ` sakishrist
@ 2015-08-11 9:42 ` Kevin Wolf
2015-08-11 10:08 ` sakishrist
8 siblings, 0 replies; 12+ messages in thread
From: Kevin Wolf @ 2015-08-11 9:42 UTC (permalink / raw)
To: qemu-devel
This is a different case. The original report used "qemu-img create" in
step 2, which results in a sparse image that refers to the backing file
for all data. Your sequence has "qemu-img convert" instead, which fully
populates disk.qcow. Therefore, in step 3, "qemu-img convert" leaves the
full allocation intact.
--
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/660366
Title:
"qemu-img convert -O qcow2 -o backing_file" makes huge images
Status in QEMU:
Fix Released
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as
expected). I.e. all data is put into the resulting image: both from
source image and "backing" image.
Expected behavior is to put only data that is not present in
backing_file.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/660366/+subscriptions
^ permalink raw reply [flat|nested] 12+ messages in thread* [Qemu-devel] [Bug 660366] Re: "qemu-img convert -O qcow2 -o backing_file" makes huge images
2010-10-14 8:28 [Qemu-devel] [Bug 660366] [NEW] "qemu-img convert -O qcow2 -o backing_file" makes huge images Ildar
` (7 preceding siblings ...)
2015-08-11 9:42 ` Kevin Wolf
@ 2015-08-11 10:08 ` sakishrist
8 siblings, 0 replies; 12+ messages in thread
From: sakishrist @ 2015-08-11 10:08 UTC (permalink / raw)
To: qemu-devel
My mistake. It's different case than mine. Above sequence (original
report) works fine.
But I do not really understand why the same is not achieved in my case.
I use the convert instead of the create to get a full image in qcow
format. From that point, the desired behaviour is to create a qcow that
is based on the one created from the first convert and contain only the
changes. Why would the second convert populate the whole image again?
Thanks in advance.
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/660366
Title:
"qemu-img convert -O qcow2 -o backing_file" makes huge images
Status in QEMU:
Fix Released
Bug description:
$ dd if=/dev/urandom bs=1M of=1.img count=4
4+0 records in
4+0 records out
4194304 bytes (4,2 MB) copied, 1,0413 s, 4,0 MB/s
$ qemu-img create -f qcow2 -b 1.img 2.img
Formatting '2.img', fmt=qcow2 size=4194304 backing_file='1.img' encryption=off cluster_size=0
$ qemu-img convert -O qcow2 -o backing_file=1.img 2.img 3.img
$ du -h ?.img
4,1M 1.img
144K 2.img
4,3M 3.img
The conversion result is bigger then the source!
It appears that "-o backing_file" is not applied to data (as
expected). I.e. all data is put into the resulting image: both from
source image and "backing" image.
Expected behavior is to put only data that is not present in
backing_file.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/660366/+subscriptions
^ permalink raw reply [flat|nested] 12+ messages in thread