Linux HD question

[The Stinger]

At my work we have a Linux server which stores all work data.
Now my boss told me that the guy who installed it said that if the primary
hd broke down then it would use the 2nd hd and boot Linux from it.
I looked at a hd info tool in Linux and it only showed 1 hd, but the server has 2.
Is it possible that it'll boot from the other if the primary crashes?

My boss also thinks the data will be saved.
Now I hardly know Linux, but I doubt it saves the data and puts it on the other drive, right?

[Hudson]

Are you running in RAID 0+1 striped?

[Crosma]

Sounds more like a simple RAID 1 set-up to me. You can't have a nested RAID on just two disks.

[The Stinger]

So if it's running RAID I would only be able to save of one disk(if the other one broke down), right?

I'll try find out what type of configuration it's running when I'm at work again.

[Crosma]

So if it's running RAID I would only be able to save of one disk(if the other one broke down), right?If one disk breaks down, the other will carry on as normal. That's the redundancy. If both disks are working, both disks will be identical at all times.

If one breaks and you want to replace it, you need to duplicate the working disk exactly (which is best done in Linux by booting from CD/USB and using dd to copy the data - while the disks are unmounted, of course - including all of the boot data, etc. (Like, dd if=/dev/hda of=/dev/hdb bs=64M. The increased block-size will improve the speed. Make sure you enable DMA or it will take at least twice as long). RAID requires identical disks, not close to identical. Then you'll have your working RAID back when you boot from the harddisk.

That's it.

[The Stinger]

Alright, thanks for the info. :)