cpu, load and notifications

hi to all

I've an ML310 with 1 dualcore cpu, and I use it as NAS for some VMs installed on XenServer on other ProLiant server. Network is gigabit.

I've no slow / problems with VM, but when I work on some VM (copying files, programs installation, and so on...) load average is about 5 (!). If I start htop cpu is about 3-5%, ram is 350MB of 4GB. I have to worry about load average?

Another thing is that I've configured notifications, and when load average is high I receive many email, too much.... But I don't want disable it, is it possible to configure that OMV send me notification every 15-30 minutes or only once per hour and not always?

Thanks

it makes sense, as I didn't write "I want receive mail after 30 minutes", but that I don't want receive 30 mails in 30 minutes...