I did a script which run around 4 o'clock in the morning, for backup all the mysql databases and the config file for 250 linux vm. The problem is that it tooks ages for complete and more than 50% of these vm, need more than 8 hours for complete.
More or less all the vm had the same configuration,I mean

• Same amount of ram
• same amount of disk space
• same number of cpu
  
• Debian 6.0.5

I am saving these backup on amazon s3, because is the cheapest solutions that I've found. Now my questions is:
Has anyone some solutions or suggestions about that?
On one blog I've read that probably the ionice and nice combination could be good work around about that. any thought?