Can you add drives to an existing RAID 1 volume?

[skaughtz]

I will try to keep this simple.

I have a two 250GB drives in a RAID 1 setup that I use for simple file storage for personal and work. One of the drives is on its way out (acting wonky and CrystalDiskInfo indicates a Current Pending Sector Count of 200). I have two more 250GB drives on the way. My understanding is that if I swap the bad drive for the new drive, the setup will rebuild from the existing good drive (if anyone could confirm this, I'd appreciate it) and no muss no fuss there. But I snagged two drives, and would like to add another to have redundancy across three drives. If I did that, would I need to wipe and create a new volume across all three drives, or would the good drive rebuild the setup by mirroring itself on the other two? If the former, I have read but am still somewhat confused about a RAID 1 that utilizes something like a 2+1 setup, where one drive exists as an emergency backup to step in should one of the other two fail. Any info on that would be helpful.

 

I just finished backing up the files on a few external sources, so the data is safe regardless of what I do.

 

Thanks in advance.

[da na]

How are you doing RAID? An onboard controller like an Intel RST or RAID card, or a software solution? In either case you should be able to add drives to a mirrored array and rebuild AFAIK. (At least, that's how it works on my RST system.)

[skaughtz]

13 minutes ago, Mel0nMan said:

How are you doing RAID? An onboard controller like an Intel RST or RAID card, or a software solution? In either case you should be able to add drives to a mirrored array and rebuild AFAIK. (At least, that's how it works on my RST system.)

Using the onboard controller on an old ASRock Z75 Pro 3 (LGA 1155).

 

I have never had to rebuild a RAID volume before, so before I potentially brain fart while installing the new drives and wipe the existing one or something stupid like that, I thought I would get the details on it.

[Robchil]

rebuild buy plugging new harddrive on the old sata cable/port. and restart. that's how raid works. it will look for the second drive and when it find one with no version on it it will start rebuilding. just make sure it's absolutly empty before you plug it in. 

 

some older controllers makes you confirm rebuild in the raid/disk controller bios. but it should show up and give you that option if it doesn't automaticly starts to rebuild. 

to add the 3rd disk you will have to access the controller bios anyway and in the existing raidset add the 3rd disk.. what you are talking about is actually RAID 5.. with 3 disks one for parity. they are all in use still then so any can fail and be replaced.

 

it's usually first one dedicated raid systems you will find 2+1 setups.. not that i can recall it atm. that's usually for raid 5.. then called raid 6 if you have a spare.  raid 10 is mirrored raid 5.. etc. 

 

if you want to replace both old disks in the end.. using 2 new ones. you will have to let the first replacement rebuild. then remove the last old disk and rebuild the last new one. 

that's actually the old way of doing quick system backup from mirrored system drives in servers... take out one