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Case A
internal snapshots
Χρειάζεται το image format της εικονικής μηχανής, να είναι qcow2
Το qcow2 σημαίνει: Qemu Copy On Write v2
και υποστηρίζει snapshots.
# virsh start test Domain test started # virsh snapshot-create-as test Domain snapshot 1363290212 created # virsh snapshot-list test Name Creation Time State ------------------------------------------------------------ 1363290212 2013-03-14 21:43:32 +0200 running # virsh snapshot-create-as test Domain snapshot 1363291168 created # virsh snapshot-list test Name Creation Time State ------------------------------------------------------------ 1363290212 2013-03-14 21:43:32 +0200 running 1363291168 2013-03-14 21:59:28 +0200 running
libvirtd
# pwd -P /var/lib/libvirt/qemu/snapshot/test # ls -l total 16 -rw------- 1 root root 4242 Μάρ 14 21:59 1363290212.xml -rw------- 1 root root 4293 Μάρ 14 22:04 1363291168.xml
Πάντα εργαζόμαστε στο τελευταίο running snapshot και κρατάει εσωτερικά (δλδ μέσα στον δίσκο) τα snapshots
# qemu-img info test.qcow2 image: test.qcow2 file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 1.3G cluster_size: 65536 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 1 1363290212 196M 2013-03-14 21:43:32 00:01:02.984 # qemu-img info test.qcow2 image: test.qcow2 file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 1.6G cluster_size: 65536 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 1 1363290212 196M 2013-03-14 21:43:32 00:01:02.984 2 1363291168 268M 2013-03-14 21:59:28 00:16:49.119
Πως επιστρέφουμε στο αρχικό image
# virsh snapshot-delete test 1363291168 Domain snapshot 1363291168 deleted # qemu-img info test.qcow2 image: test.qcow2 file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 1.8G cluster_size: 65536 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 1 1363290212 196M 2013-03-14 21:43:32 00:01:02.984 # virsh snapshot-delete test 1363290212 Domain snapshot 1363290212 deleted # qemu-img info test.qcow2 image: test.qcow2 file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 1.8G cluster_size: 65536
Case B
# qemu-img info winxp.img.spars image: winxp.img.spars file format: raw virtual size: 5.0G (5368709120 bytes) disk size: 5.0G # ls -l winxp.img.spars -rw-r--r-- 1 ebal ebal 5368709120 Μάρ 15 12:30 winxp.img.spars # qemu-img convert -p -f raw -O qcow2 winxp.img.spars winxp.qcow2 # lrzip winxp.qcow2.spars Output filename is: winxp.qcow2.spars.lrz winxp.qcow2.spars – Compression Ratio: 2.235. Average Compression Speed: 6.677MB/s. Total time: 00:06:08.76 # ls -l σύνολο 3642396 -rw-r--r-- 1 root root 2576809984 Μάρ 15 13:33 winxp.qcow2.spars -rw-r--r-- 1 root root 1153117496 Μάρ 15 13:46 winxp.qcow2.spars.lrz # qemu-img info winxp.qcow2.spars image: winxp.qcow2.spars file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 2.4G cluster_size: 65536 # virsh snapshot-create-as test Domain snapshot 1363348525 created # virsh snapshot-list test Name Creation Time State ------------------------------------------------------------ 1363348525 2013-03-15 13:55:25 +0200 running # qemu-img info winxp.qcow2.spars image: winxp.qcow2.spars file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 2.7G cluster_size: 65536 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 1 1363348525 254M 2013-03-15 13:55:25 00:01:41.575 # virsh snapshot-delete test 1363348525 Domain snapshot 1363348525 deleted # qemu-img info winxp.qcow2.spars image: winxp.qcow2.spars file format: qcow2 virtual size: 5.0G (5368709120 bytes) disk size: 2.7G cluster_size: 65536