From: Lenny Helpline <1810603@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [Bug 1810603] Re: QEMU QCow Images grow dramatically
Date: Mon, 28 Jan 2019 09:46:39 -0000 [thread overview]
Message-ID: <154866879946.29740.13554399095004528872.malone@soybean.canonical.com> (raw)
In-Reply-To: 154670237006.5111.1505843603378488710.malonedeb@wampee.canonical.com
> Looking at the file size isn't helpful. The 23 GB
> are the space that is actually used. You can use 'du -h'
> to confirm this, but I think it gets the number in the exact same way as qemu-img.
Are you sure about that? My OS complains that the disk is full. I can't
even start any VM anymore. That's the reason why I've opened this
ticket. Otherwise I wouldn't care....
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 63G 0 63G 0% /dev
tmpfs 13G 164M 13G 2% /run
/dev/md1 455G 455G 0 100% /
# du -sh W10-CLIENT01-0.img
115G W10-CLIENT01-0.img
Vs original file size:
8GB W10-CLIENT01-0.img
How's that possible?
# qemu-img info W10-CLIENT01-0.img
image: W10-CLIENT01-0.img
file format: qcow2
virtual size: 320G (343597383680 bytes)
disk size: 114G
cluster_size: 65536
backing file: /var/lib/libvirt/images/W10-MASTER-IMG.qcow2
Snapshot list:
ID TAG VM SIZE DATE VM CLOCK
1 1 6.4G 2019-01-04 14:33:47 01:14:37.729
Format specific information:
compat: 1.1
lazy refcounts: false
refcount bits: 16
corrupt: false
--
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https://bugs.launchpad.net/bugs/1810603
Title:
QEMU QCow Images grow dramatically
Status in QEMU:
New
Bug description:
I've recently migrated our VM infrastructure (~200 guest on 15 hosts)
from vbox to Qemu (using KVM / libvirt). We have a master image (QEMU
QCow v3) from which we spawn multiple instances (linked clones). All
guests are being revert once per hour for security reasons.
About 2 weeks after we successfully migrated to Qemu, we noticed that
almost all disks went full across all 15 hosts. Our investigation
showed that the initial qcow disk images blow up from a few gigabytes
to 100GB and more. This should not happen, as we revert all VMs back
to the initial snapshot once per hour and hence all changes that have
been made to disks must be reverted too.
We did an addition test with 24 hour time frame with which we could
reproduce this bug as documented below.
Initial disk image size (created on Jan 04):
-rw-r--r-- 1 root root 7.1G Jan 4 15:59 W10-TS01-0.img
-rw-r--r-- 1 root root 7.3G Jan 4 15:59 W10-TS02-0.img
-rw-r--r-- 1 root root 7.4G Jan 4 15:59 W10-TS03-0.img
-rw-r--r-- 1 root root 8.3G Jan 4 16:02 W10-CLIENT01-0.img
-rw-r--r-- 1 root root 8.6G Jan 4 16:05 W10-CLIENT02-0.img
-rw-r--r-- 1 root root 8.0G Jan 4 16:05 W10-CLIENT03-0.img
-rw-r--r-- 1 root root 8.3G Jan 4 16:08 W10-CLIENT04-0.img
-rw-r--r-- 1 root root 8.1G Jan 4 16:12 W10-CLIENT05-0.img
-rw-r--r-- 1 root root 8.0G Jan 4 16:12 W10-CLIENT06-0.img
-rw-r--r-- 1 root root 8.1G Jan 4 16:16 W10-CLIENT07-0.img
-rw-r--r-- 1 root root 7.6G Jan 4 16:16 W10-CLIENT08-0.img
-rw-r--r-- 1 root root 7.6G Jan 4 16:19 W10-CLIENT09-0.img
-rw-r--r-- 1 root root 7.5G Jan 4 16:21 W10-ROUTER-0.img
-rw-r--r-- 1 root root 18G Jan 4 16:25 W10-MASTER-IMG.qcow2
Disk image size after 24 hours (printed on Jan 05):
-rw-r--r-- 1 root root 13G Jan 5 15:07 W10-TS01-0.img
-rw-r--r-- 1 root root 8.9G Jan 5 14:20 W10-TS02-0.img
-rw-r--r-- 1 root root 9.0G Jan 5 15:07 W10-TS03-0.img
-rw-r--r-- 1 root root 10G Jan 5 15:08 W10-CLIENT01-0.img
-rw-r--r-- 1 root root 11G Jan 5 15:08 W10-CLIENT02-0.img
-rw-r--r-- 1 root root 11G Jan 5 15:08 W10-CLIENT03-0.img
-rw-r--r-- 1 root root 11G Jan 5 15:08 W10-CLIENT04-0.img
-rw-r--r-- 1 root root 19G Jan 5 15:07 W10-CLIENT05-0.img
-rw-r--r-- 1 root root 14G Jan 5 15:08 W10-CLIENT06-0.img
-rw-r--r-- 1 root root 9.7G Jan 5 15:07 W10-CLIENT07-0.img
-rw-r--r-- 1 root root 35G Jan 5 15:08 W10-CLIENT08-0.img
-rw-r--r-- 1 root root 9.2G Jan 5 15:07 W10-CLIENT09-0.img
-rw-r--r-- 1 root root 41G Jan 5 15:08 W10-ROUTER-0.img
-rw-r--r-- 1 root root 18G Jan 4 16:25 W10-MASTER-IMG.qcow2
You can reproduce this bug as follow:
1) create an initial disk image
2) create a linked clone
3) create a snapshot of the linked clone
4) revert the snapshot every X minutes / hours
Due the described behavior / bug, our VM farm is completely down at
the moment (as we run out of disk space on all host systems). A quick
fix for this bug would be much appreciated.
Host OS: Ubuntu 18.04.01 LTS
Kernel: 4.15.0-43-generic
Qemu: 3.1.0
libvirt: 4.10.0
Guest OS: Windows 10 64bit
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1810603/+subscriptions
next prev parent reply other threads:[~2019-01-28 10:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-05 15:32 [Qemu-devel] [Bug 1810603] [NEW] QEMU QCow Images crow dramatically Lenny Helpline
2019-01-05 16:19 ` Eric Blake
2019-01-05 16:25 ` Eric Blake
2019-01-07 18:38 ` [Qemu-devel] [Bug 1810603] Re: QEMU QCow Images grow dramatically Peter Maydell
2019-01-08 8:30 ` Lenny Helpline
2019-01-08 14:46 ` Eric Blake
2019-01-08 15:41 ` Eric Blake
2019-01-11 13:06 ` Kevin Wolf
2019-01-18 11:01 ` Lenny Helpline
2019-01-18 12:24 ` Kevin Wolf
2019-01-28 9:46 ` Lenny Helpline [this message]
2021-02-03 14:01 ` Thomas Huth
2021-04-05 4:17 ` Launchpad Bug Tracker
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