CODEWITHSUNDEEP
qemuhole-punching
wayen
wayen

Reputation: 53

remove qcow2 image file's holes

I use a tool named virt-sparsify to free disk space a qcow2 image file occupies.

It works and the file becomes a sparse file.

root@ubuntu:/test# ls -lsh test.qcow2

8.7G -rw-r--r-- 1 root root 15G Jan 19 11:05 test.qcow2

As shown above, the disk size allocated for the file is smaller than its actual size. It means there are “holes” in the file. Now I want to remove these holes inside it. Does anyone know how to achieve this purpose？

Upvotes: 1

Views: 2109

Answers (1)

Christian Ehrhardt
Christian Ehrhardt

Reputation: 151

You can't really "take away" the sparse flag. Tools try to help by keeping the flag alive e.g. cp when copying.

You can easily get a non-sparse version of that file via

cp --sparse=never test.qcow2 test-nosparse.qcow2

The same way you can make a partially zeroed out file a sparse file

cp --sparse=always file.qcow2 file-sparse.qcow2

See "sparse" in man cp

Upvotes: 1

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