Here's some further information from the VMware manuals. I searched for the word snapshot in all manuals here: http://pubs.vmware.com/vi35/wwhelp/wwhimpl/js/html/wwhelp.htm
First, you CAN take a snapshot of a powered-off machine. From the manual: "You can take a snapshot while a virtual machine is powered on, powered off, or suspended. If you are suspending a virtual machine, wait until the suspend operation has finished before taking a snapshot. You must power off the virtual machine before taking a snapshot if the virtual machine has multiple disks in different disk modes." Also: Note Snapshots of raw disks, RDM physical mode disks, and independent disks are not supported. Also from the manual: "When you take a snapshot, be aware of other activity going on in the virtual machine and the likely effect of reverting to that snapshot. In general, it is best to take a snapshot when no applications in the virtual machine are communicating with other computers. The potential for problems is greatest if the virtual machine is communicating with another computer, especially in a production environment. For example, if you take a snapshot while the virtual machine is downloading a file from a server on the network, the virtual machine continues downloading the file, communicating its progress to the server. If you revert to the snapshot, communications between the virtual machine and the server are confused and the file transfer fails. Another example is taking a snapshot while an application in the virtual machine is sending a transaction to a database on a separate machine. If you revert to that snapshot-especially if you revert after the transaction starts but before it has been committed-the database is likely to be confused." This does not sound like I don't have to worry about the state of my machine while taking a snapshot. --- W. Curtis Preston Backup Blog @ www.backupcentral.com VP Data Protection, GlassHouse Technologies > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of Curtis Preston > Sent: Thursday, February 28, 2008 10:21 AM > To: Steven Kurylo; [email protected] > Subject: RE: Backing up VMware-VMs > > After consulting with two VMware experts, I stand by my original > statement, that a snapshot of a vm is a crash consistent copy, which > means that it's just like someone pulled the power plug. It is NOT like > someone suspending a VM. > > There are 3rd party products that provide additional levels of > consistency (netapp, falconstor that I know of), but the default VMware > snapshots are crash consistent, not transactional consistent. > > --- > W. Curtis Preston > Backup Blog @ www.backupcentral.com > VP Data Protection, GlassHouse Technologies > > > -----Original Message----- > > From: Steven Kurylo [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, February 27, 2008 2:06 PM > > To: Curtis Preston; [email protected] > > Subject: Re: Backing up VMware-VMs > > > > Curtis Preston wrote: > > > Unless you're coordinating with the OS, then taking a VMware > snapshot > > > and copying it is equivalent to pulling the power plug on a server. > > > Will it power back up without corruption? 99.9% of the time, yes. > Has > > > anyone who has been in the biz for a while had a scenario where > > > powercycling a box caused a corrupted OS disk? I'd say so. > > > > > Thats false. > > > > Its the same thing as suspending a VM. When you restore the you can > > either restore it as if the power was shut off or resume it as if > > nothing had happened. Obviously the outside world has changed, so > > network connections, the time, etc, will have changed.
