为什么rsync --sparse产生比原始qcow2文件更大的qcow2文件

Question

问题：

当我用虚拟机将整个磁盘复制到带有rsync的密码盘时 - 新磁盘上的磁盘映像（qcow2文件）比原始文件大。

旧磁盘： / dev / sda1 =＆gt; / ssdstor

新磁盘： / dev / sdb1 =＆gt; /新

详细说明：

设备： 2x SSD Curcial M500 960GB固件MU5

操作系统： Proxmox 3.4

Filesyste： XFS

命令：

rsync -axHv --force --progress --stats --sparse /ssdstor/ /new/

Rsync版本： dpkg -L | grep rsync

ii  rsync                                         993.1.1-1                     amd64        fast, versatile, remote (and local) file-copying tool

第一次复制后
• 文件/磁盘比较* （检查一切是否正确转移）

rsync -axHv --dry-run --force --progress --stats --sparse / ssdstor / / new /

sending incremental file list

Number of files: 90,545 (reg: 70,269, dir: 9,395, link: 10,817, dev: 4, special: 60)
Number of created files: 0
Number of deleted files: 0
Number of regular files transferred: 0
Total file size: 634,456,255,674 bytes
Total transferred file size: 0 bytes
Literal data: 0 bytes
Matched data: 0 bytes
File list size: 65,536
File list generation time: 0.001 seconds
File list transfer time: 0.000 seconds
Total bytes sent: 2,097,654
Total bytes received: 9,993

sent 2,097,654 bytes  received 9,993 bytes  1,405,098.00 bytes/sec
total size is 634,456,255,674  speedup is 301,025.86 (DRY RUN)

mount | egrep'（sda | sdb）'

/dev/sda1 on /ssdstor type xfs (rw,noatime,nodiratime,attr2,inode64,noquota)
/dev/sdb1 on /new type xfs (rw,noatime,nodiratime,attr2,inode64,noquota)

df -h | egrep'（sda | sdb）'

/dev/sda1             894G    388G  506G   44% /ssdstor
/dev/sdb1             894G    430G  465G   49% /new

ls -alshR / ssdstor | grep qcow2

77G -rw-r--r--  1 root root 103G Jul 14 09:09 vm-100-disk-1.qcow2
6,2G -rw-r--r--  1 root root  14G Jul 14 09:07 vm-101-disk-1.qcow2
2,0G -rw-r--r--  1 root root 4,1G Jul 14 09:07 vm-101-disk-2.qcow2
17G -rw-r--r--  1 root root 61G Feb 18 09:10 vm-102-disk-1.qcow2
40G -rw-r--r--  1 root root 78G Jul 14 09:06 vm-103-disk-1.qcow2
40G -rw-r--r--  1 root root 41G Jul 14 09:05 vm-103-disk-2.qcow2
31G -rw-r--r--  1 root root 44G Jul 14 09:05 vm-104-disk-1.qcow2
5,2G -rw-r--r--  1 root root 41G Mai  1 01:00 vm-105-disk-2.qcow2
63G -rw-r--r--  1 root root 65G Jul 14 10:04 vm-106-disk-1.qcow2
26G -rw-r--r--  1 root root 65G Jul 14 09:14 vm-107-disk-2.qcow2
51G -rw-r--r--  1 root root 51G Mai 19 21:21 vm-108-disk-1.qcow2

ls -alshR / new | grep qcow2

79G -rw-r--r--  1 root root 103G Jul 14 09:09 vm-100-disk-1.qcow2
6,2G -rw-r--r--  1 root root  14G Jul 14 09:07 vm-101-disk-1.qcow2
2,0G -rw-r--r--  1 root root 4,1G Jul 14 09:07 vm-101-disk-2.qcow2
17G -rw-r--r--  1 root root 61G Feb 18 09:10 vm-102-disk-1.qcow2
40G -rw-r--r--  1 root root 78G Jul 14 09:06 vm-103-disk-1.qcow2
41G -rw-r--r--  1 root root 41G Jul 14 09:05 vm-103-disk-2.qcow2
37G -rw-r--r--  1 root root 44G Jul 14 09:05 vm-104-disk-1.qcow2
34G -rw-r--r--  1 root root 41G Mai  1 01:00 vm-105-disk-2.qcow2
63G -rw-r--r--  1 root root 65G Jul 14 10:04 vm-106-disk-1.qcow2
33G -rw-r--r--  1 root root 65G Jul 14 09:14 vm-107-disk-2.qcow2
51G -rw-r--r--  1 root root 51G Mai 19 21:21 vm-108-disk-1.qcow2

有人有想法吗？

更多测试：

cp --sparse = always vm-105-disk-2.qcow2 vm-105-disk-2.qcow2.new

5,2G -rw-r--r--  1 root root 41G Jul 16 08:07 vm-105-disk-2.qcow2
 34G -rw-r--r--  1 root root 41G Jul 16 11:51 vm-105-disk-2.qcow2.new