If one of your Raid 5 disks fails or one or more drives from your Raid 10 array you will hear beeping. There are two ways to disable the beeping and start on your way to recovery. You can either enter your Raid card’s bios management console and hitting a key combination like Control + G. You should see a message prompting you to enter it during POST. In there you should see a silence alarm button.
You can also disable it from the software array management suite. On Dell this is open manage and there will be a silence alarm button there as well.
But all in all you need to correct the failed drive or other condition to rectify it but it sure is hard to do with all that beeping!!