Im confused now on what RAID card I should buy.I will be setting up RAID 1 So that all data are mirrored to another HDD and this is solely for backup purpose.I will need a mid range RAID cards.Not cheap ones or too costly ones.
Also I would like to know,If I have a RAID 1 Config and one of the HDD fails,Does replacing that drive is enough and the data is again synced to the new HDD automatically?
And also If I ever need to recover data from one of the hard Disk which is good,Will it be possible?(Considering 1 HDD has failed and the other is working.).Thank you.
I'd highly recommend for what you're looking at just sticking with the RAID 1. First off, RAID is NOT a backup solution. It's meant to provide continual up-time, and a "side effect" is that it duplicates and protects your data. However, you still need to have some form of actual backup strategy completely separate from your RAID implemented. The reason I'd recommend RAID 1 is because all of your data resides on each drive, there's no striping or parity of data, so in the event of a catastrophic failure or the need to migrate, you can pull out your hard drive, move it to any other computer, and have access to all of the data. If you did a RAID 5 or RAID 10 array, you can't do this as your RAID array is completely dependent then on THAT RAID controller. I've had this happen before with customers where it has been a last-level life saver. When the server goes down, they can just pull one hard drive, install it in any of their other computers, and they have all of their data within minutes. No waiting for replacement drives and rebuilding data or having to recover backup images or anything.
I agree with Das-stig that the 6805 can be a great card, I've got one here that has offered great performance and at a good price. However, I've had problems getting ESXi running and recognizing the card at all, so be cautious if your plans are to run ESXi.
Another option would be an HP P410/256 MB SmartArray RAID controller, which can be had for very good costs on several retailers, and has full support for Windows Server OS, ESXi, and several Linux distros. I've also used several of these cards and they too offer good performance.
Some RAID controllers, in the event of a hard drive failure, will require you to go into their BIOS configuration or use some client installed software utility to actually begin the rebuilding of data onto a new replacement drive.