Dennis J. wrote: > Hi, > What is the best way to deal with I/O load when running several VMs on a > physical machine with local or remote storage? > > What I'm primarily worried about is the case when several VMs cause disk > I/O at the same time. One example would be the "updatedb" cronjob of the > mlocate package. If you have say 5 VMs running on a physical System with a > local software raid-1 as storage and the all run updatedb at the same time > that causes all of them to run really slowly because the starve each other > fighting over the disk. > > In this particular case, I would edit /etc/crontab on each VM and move the update at another time instead of the traditional 4:02 > What is the best way to soften the impact of such a situation? Does it make > sense to use a hardware raid instead? How would the raid type affect the > performance in this case? Would the fact that the I/O load gets distributed > across multiple spindles in, say, a 4 disk hardware raid-5 have a big > impact on this? > > I'm currently facing the problem where I fear that random disk I/O by too > many VMs on a physical system could cripple their performance even though I > have plenty of CPU cores/RAM left to run them. > > Has anyone experience with this problem and maybe some data to shed some > light on this potential bottleneck for virtualization? > > Regards, > Dennis >