software raid - just one more question

[Vu Pham]

I was practicing "destroying and rebuilding" the software raid1 and raid 
5 devices last night. I noticed that it slows the sytem down a lot when 
the rebuidling process is running.

Under mdadm, is there any parameter that controls how fast the 
rebuilding process is ? Can I slow the rebuild process to have less 
impact on the system ?  I understand that then it will take longer time 
for that process finishes.

I looked at the mdadm man last night but I could not find it. I might 
miss it :(

I promise this is my last question about software raid .... for today :)

Thanks,

Vu