[Qemu-devel] qcow2 disk size information may be error while it is larger than 2T capacity

[Guozhonghua]

Hi, everyone

 

We have one qemu image file which size is 2348439044096, format is qcow2.

But as we get its information with the command qemu-img info, the disk size is 139G.

The info is as below:

 

# qemu-img info APCD-CSSJK

image: APCD-CSSJK

file format: qcow2

virtual size: 1.9T (2097152000000 bytes)

disk size: 139G

cluster_size: 2097152

backing file:  /vms/storage/APCD-JHSJK_base_0

 

# qemu-img info APCD-JHSJK_base_0

image: APCD-JHSJK_base_0

file format: qcow2

virtual size: 1.0T (1101004800000 bytes)

disk size: 34G

cluster_size: 2097152

 

# ls -al APCD-JHSJK_base_0

-rw-r--r-- 1 root root 36012294144 Aug  9 00:31 APCD-JHSJK_base_0

address@hidden: /vms/storage# ls -al APCD-CSSJK

-rw------- 1 root root 2348439044096 Aug 19 17:36 APCD-CSSJK

 

As calculated with the image size, so the information of the disk size display may be wrong:

(2348439044096 – 2*1024*1024*1024*1024) /( 1024*1024*1024) = 139.154296875 G

 

As we convert the APCD-CSSJK with –O qcow2, the destination image is larger then 500G, which is larger than 139G + 36G; and we stop the converting.

qemu-img convert -O qcow2 APCD-CSSJK apcd_csscssjk-gzh

 

# ls -al apcd* ;date

-rw-r--r-- 1 root root 483043311616 Aug 19 20:01 apcd_csscssjk-gzh

Tue Aug 19 20:01:34 CST 2014

 

# qemu-img info apcd_csscssjk-gzh

image: apcd_csscssjk-gzh

file format: qcow2

virtual size: 1.9T (2097152000000 bytes)

disk size: 469G

cluster_size: 2097152

 

Is the disk size segment is limited to 2T in qemu? Or there are some patch for it.

 

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