[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [Bug 322602] Re: Snapshot usage makes qcow2 image unusable
From: |
Thomas Huth |
Subject: |
[Qemu-devel] [Bug 322602] Re: Snapshot usage makes qcow2 image unusable due to large tables |
Date: |
Fri, 04 Nov 2016 15:39:31 -0000 |
** Changed in: qemu
Status: New => Incomplete
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/322602
Title:
Snapshot usage makes qcow2 image unusable due to large tables
Status in QEMU:
Incomplete
Bug description:
To reproduce with 0.9.1 and svn:
- Create a 20G (or some size much greater than system RAM) qcow2 image
- Inside VM, install some OS, formatting whole drive
- Create snapshot with savevm
- Inside VM, reformat and reinstall OS
- Create snapshot with savevm
[...]
Eventually, qemu crashes, then neither qemu-img nor qemu can open the
image because memory is exhausted. The reason is that the whole
refcount_table is loaded into memory, and this refcount_table has now
become much bigger than the size of memory due to each snapshot taken
after significant changes to the disk image.
The refcount_table really needs to be loaded and used in fixed size
chunks to avoid this problem. It will only get worse as typical
storage set modifications during work sessions between snapshots
outpace the size of system RAM.
Alternatively, there needs to be a way to "rollback" a snapshot
without loading the whole disk image normally, so that a snapshot
which has made the image unusable in this way can be reversed.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/322602/+subscriptions
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Qemu-devel] [Bug 322602] Re: Snapshot usage makes qcow2 image unusable due to large tables,
Thomas Huth <=