Subscriber Terry HOTSON wrote with questions about setting up a RAID system:
Approx. 3 weeks ago i changed from XP Pro to Windows 7 (new SATA hard drive). I have now installed a 2nd SATA hard drive(new).My question is,
how do i make it RAID ? Can you assist me, thank you Terry.
There are several reasons why I could not tell Terry exactly how to set up a RAID system (a Redundant Array of Inexpensive Disks), but I could tell him one thing about the issues:
1) I haven’t used RAID — at one point I thought about it as a "neat thing to do." Then, I realized that I had no need for it — I needed drives for storage and I could use tape (old days) and image backups (today) to back up my systems. However, there’s a very important thing to remember about RAID — all except Raid 0 provide some protection against data loss because of hard drive failure. None provide protection against "brain failure" or malware attack. They really are not what I would consider a backup system.
2) Your motherboard must support RAID for the drives you want to set up as a RAID system, if you want to hook the RAID drives directly to the motherboard, or
3) If not #2, then you’ll need a SATA II or SATA III add-on interface card for your computer that provides RAID capabilities
4) All your RAID drives must be the same size
5) You must decide which flavor of RAID you want – RAID 0 or Raid 1 or RAID 0,1 etc – and there are even more complicated ones
6) What is your goal — speed or security? That will drive how many physical drives you use and which flavor of raid you use.
7) Each RAID controller has its own drivers and own instructions on how to go about setting up a RAID system using it.
RAID 0 — striping — two drives are required. Fast. Data is written in stripes alternately between first drive and second drive, including files being split between the two. Dangerous for important data, as a loss of either drive loses everything.
RAID 1 — mirroring — one drive is the master, and every write transaction is mirrored on the other hard drive. Prevents loss caused by hard drive failure. Does nothing to prevent loss by brain failure — "oh, no!" applies to both drives. It’s not a backup system, it’s a real-time duplicate.
RAID 3, 4, 5 and 6 all deal with ways of using multiple drives to handle striping and parity, in order to be able to recover from a hard drive failure. Still no protection from brain failure.
RAID 0+1 — striped then mirrored — four drives. Fast and real-time redundancy. First 2 are striping data and second 2 are mirroring what happens on the first two. Still no protection from brain failure.
And, there are more…
Terry wrote back to say:
thank you for answering the email, i solved the problem, and i think Windows 7 is excellent to arrange RAID do not need to download drivers or go into the BIOS i could do it with the OS. I chose RAID 1 (2 sata hd’s ) not fast but for a little protection. By the way i have SATA II Drives. Once again thank you very much you have a interesting site.
Terry "backed into" a solution, but it may not be a solution he was expecting.
There are two basic ways to control RAID systems — generally, they’re referred to as hardware RAID and software RAID. Hardware RAID allows the operating system to be unaware of the fact that RAID is occurring.
In doing so, all the control of the RAID activity is controlled by the RAID controller board. Software RAID, on the other hand, puts the load on the operating system (Windows 7, in this case), so it may sometimes be perceived as slowing the computer.