VMware has been working with virtualization since 1998 and has shaken up an entire industry. Many companies have been relying on this proven technology for years. It all started with VMware Workstation and today VMware vSphere with VMware ESXi and VMware vCenter Server have become an integral part of everyday IT life.
But now we come to the pitfall of VMware snapshot backup. Every normal virtual machine requires a virtual hard disk. In the case of VMware, this is a VMDK file. To protect the virtual machine from errors after installing updates or new software, the developers introduced the snapshot.
A snapshot can be created before a new installation, an upgrade or any other manipulation of the virtual machine. This means that the original virtual hard disk is frozen from that moment on. It is renamed doc1-flat.vmdk. At the same time, a new file is created: the snapshot.
It is given the name doc1-delta.vmdk. All changes are now made to the snapshot. If something goes wrong, you can return to apartment.vmdk. The problem is that you can generate several (up to 32) snapshot levels. Supposedly, each snapshot is a backup. The trap is that if even one snapshot is deleted or corrupted, all subsequent snapshots will be completely useless. The snapshot only saves the changes, not the complete data records.
VMware itself recommends that snapshots should never be used for more than 24 to 72 hours. However, many companies actually leave the server running as a snapshot for months or even years. Incidentally, this also reduces server performance, as the virtual hard disk has to be constantly remounted between the original apartment.vmdk and one or more snapshots. In any case, real backups of the entire VM should be created and all snapshots should be consolidated.
Recently, a company went out of business. The Windows server virtualized with VMware had been completely lost in a failed RAID storage. After our engineers rebuilt the RAID, they realized that there were huge snapshots and one of them was corrupted. After a few hours of hard work, Digital Recovery’s experts were able to deliver the VMware to the customer fully rebuilt.
If you want to avoid a trip to the data recovery center, don’t allow permanent snapshots on your virtual machine and choose a professional backup strategy.
If a snapshot is used during maintenance work or new installations, activate a vCenter Server alarm that notifies you if a virtual machine uses snapshots after the fact. That way, you’ll no longer fall into the VMware snapshot backup trap.
If you lose your Snapshots, you can count on our solutions to recover VMware.
