On Thursday 09 March 2006 06:42 pm, Nick wrote:
It uses parity information that it stores across all three drives. In your setup 1/3 of each drive is used for the parity information. Basically any two drives then have enough parity information to recreate the date on the third drive. With raid 5 the usable storage is C * (N -1) where C is the capacity of the drives and N is the number of them. So if you have 3 * 250GB disks the usable storage is 500GB. If two disks die at the same time kiss all your data good bye (although this is a pretty rare scenario)
What I don't understand is that when it's running with only 2 disks out of 3, it seems that it's still running OK.
So: 1. What is the consequences when RAID-5 array runs with 1 lost disk? Will it damage the data? 2. What will happen if I copy a large data (say 30MB) into the running array with 1 lost disk?