[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

How to clean up unused qcow2 clusters

From: Jakob Bohm
Subject: How to clean up unused qcow2 clusters
Date: Fri, 23 Jul 2021 15:58:31 +0200
User-agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:4.8) Goanna/20210719 Interlink/52.9.7870


As is well known, qcow2 files contain a large number of
reference counted clusters that correspond roughly to file
system blocks.

As snapshots are deleted, many clusters will become logically
freed (they are no longer referenced by any image or snapshot).

My main question is how to remove, or at least zero out, those
unused host clusters, assuming the qcow2 file is not busy (because
the virtual machine is stopped and the virtual disk is not
being accessed with any other tool)?

My secondary question is why the qcow2 specification (qcow2.txt)
is not installed with the other documentation files, and why there
is no corresponding web page (not even in the qemu Wiki)?


Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded

reply via email to

[Prev in Thread] Current Thread [Next in Thread]