Prepare VM disk before snapshot and compress
disk
# 70GB disk space zeroed by dd if=/dev/zero of=/zerofile bs=1M count=70k rm /zerofile
swap
# zero to 1GB swapfile (or partition) swopoff -a dd if=/dev/zero of=/swapfile1 bs=1M count=1k mkswap /swapfile1 swapon -a
Compress qcow2 image
qemu-img convert -O qcow2 -c /opt/stack/data/glance/images/8be7ab01-5140-4d51-bf5d-b0bcb65e8d61 /storage/openstack/jira-2017-10-08-zip.qcow
Compress results
-rw-r----- 1 1024 users 7.5G Oct 8 13:23 db-2017-10-08.qcow
-rw-r--r-- 1 1024 users 1.9G Oct 8 13:45 db-2017-10-08-zip.qcow
-rw-r----- 1 1024 users 6.4G Oct 8 13:26 home-2017-10-08.qcow
-rw-r--r-- 1 1024 users 2.9G Oct 8 14:05 home-2017-10-08-zip.qcow
-rw-r----- 1 1024 users 5.3G Oct 8 13:56 jira-2017-10-08.qcow
-rw-r--r-- 1 1024 users 3.6G Oct 8 14:00 jira-2017-10-08-zip.qcow
-rw-r----- 1 1024 users 3.8G Oct 8 13:24 noc-2017-10-08.qcow
-rw-r--r-- 1 1024 users 1.4G Oct 8 13:40 noc-2017-10-08-zip.qcow
-rw-r----- 1 1024 users 8.0G Oct 8 13:22 wiki-2017-10-08.qcow
-rw-r--r-- 1 1024 users 5.5G Oct 8 13:36 wiki-2017-10-08-zip.qcow
Compress ratio for different images
| Image | Disk | Size1 | Size2 | % | description |
|---|---|---|---|---|---|
| db | 20G | 7.5G | 1.9G | 25% | postgresql |
| wiki | 80G | 8.0G | 5.5G | 68% | attlassian confluence |
| jira | 80G | 5.3G | 3.6G | 67% | Atlassian jira |
| home | 20G | 6.4G | 2.9G | 45% | nginx |
| noc | 20G | 3.8G | 1.4G | 36% | zabbix |
size1 - size after disk export from open stack
size2 - size after disk compress by qemu-img
