which one first W7 or RAID in BIOS?

[pb126]

I am setting up RAID for the first time on a new build. Mobo is Gigabyte P55-UD4P, i&-860. I have just completed the BIOS update to F6, 2 hard drives are installed. I have W7 Ultimate CD at the ready. Should I:
1. first install W7 on one of the hard drives and after that go into the BIOS and set up RAID1 with the Intel or Gigabyte RAID controller and after that the OS will get automatically mirrored;
OR
2. first setup the two drives as a RAID1 array in the BIOS (I want to mirror the OS in case of hard drive failure) and then load W7 which will then get automatically loaded onto both drives at once?
Thank you for any suggestions.

[The Wise Monkey]

Definitely set up the RAID array first. You can do it afterwards, but it will just take ages to set up the mirror if you do it when there is loads of data to copy.

[pb126]

Thanks WM.
Now, if I want to set up a partition on the RAIDed disk (ie a C: driver of 256Mb and a D: of 744Mb) do I do this before or after I set up the RAID?
idea here is that I would install OS and apps on the 256 Mb partition for speed and the rest of the drive would be used for some infrequently used stuff.
Data goes on a third drive.

[The Wise Monkey]

You can set up the partitions as part of the Windows installation process, after you have constructed the RAID array.

Also, I think you mean GB instead of MB. :)

[pb126]

Thanks WM. Correct, I meant GB...

I found that the setup was quite easy. What I ended up doing was setting up 256Gb of the 1Tb physical disks as RAID1 (for the OS and business apps) and then it let me set up the remaining 744GB as a RAID0 strip. I figured I would install the games on the striped array for higher speed but I don't know if having the mirrored array for the OS and the striped array for the Games on the same physical drive will negate any advantage I am trying to get.

I did have to load up the latest chipset drivers from the Gigabyte website which were the Intel SATA RAID drivers, which seemed to load the latest version of Intel Matrix Storage. It seems like IMS takes care of the Windows 7 part of the RAID stuff and can independently setup arrays also although I confess to not quite understanding the intricacy of all this. All in all the RAID setup went pretty painlessly.

The Gigabyte tech whom I spoke to said typically people stripe the OS for speed (?? I thought it was better to mirror so that if one drive dies you still have a functioning OS) and mirror the data drives (that I was going to do as well, with separate drives as I have 4 drives in my HAF922 now).

[The Wise Monkey]

Glad you got it all set up and working.

The kind of people that usually use RAID are enthusiasts or people working on servers. Enthusiasts, such as some people on this site (me included!), tend to reformat every so often just to keep things clean, so losing the OS isn't such a big deal. However, important data such as work stuff etc. needs to have backups, and a RAID 1 array is easier than doing external backups to a separate HD.

For servers, the tendency now is to use RAID 5, or RAID 10 - you can read up on these on Wikipedia, but essentially the try to combine the best of both RAID 0 and RAID 1.