Libro sobre Proxmox maestria
Compression
By default, the LZO compression method is selected. LZO (http://en.wikipedia. org/wiki/Lempel-Ziv-Oberhumer) is based on a lossless data compression algorithm, designed with the decompression ratio in mind. LZO is capable to do fast compression and even faster decompressions. GZIP will create smaller backup files at the cost of high CPU usage to achieve a higher compression ratio. Since higher compression ratio is the main focal point, it is a slow backup process. Do not select the None compression option, since it will create large backups without compression. With the None method, a 200 GB RAW disk image with 50 GB used will have a 200 GB backup image. With compression turned on, the backup image size will be around 70-80 GB.
Typically, all running virtual machine backups occur with the Snapshot option. Do not confuse this Snapshot option with Live Snapshots of VM. The Snapshot mode allows live backup while the virtual machine is turned on, while Live Snapshots captures the state of the virtual machine for a certain point in time. With the Suspend or Stop mode, the backup task will try to suspend the running virtual machine or forcefully stop it prior to commencing full backup. After backup is done, Proxmox will resume or power up the VM. Since Suspend only freezes the VM during backup, it has less downtime than the Stop mode because VM does not need to go through the entire reboot cycle. Both the Suspend and Stop modes backup can be used for VM, which can have partial or full downtime without disrupting regular infrastructure operation, while the Snapshot mode is used for VMs that can have a significant impact due to their downtime.
Snapshots are a great way to preserve the state of a virtual machine. It is much faster compared to full backup since it does not copy the data. Snapshot is not really a backup in a way and does not perform granular level backup. It captures the state in a point in time and allows rollback to that previous state. Snapshot is a great feature to be used in between full backups. The Proxmox snapshot even allows to capture memory of the virtual machine, so when rolled back, it is almost as if it never changed. The following screenshot is our virtual machine pmxUB01 without any snapshot:
Virtual Machine 102 ('pmxUB01') on node 'pmxvm01'