On 9/14/2011 6:13 PM, Istvan Gabor wrote:
2011. szeptember 14. 5:31 napon "David C. Rankin"<drankinatty@suddenlinkmail.com> írta:
On 09/13/2011 08:13 PM, George OLson wrote:
snip
You are correct - BIOS RAID is not an option if you want to save your current install. (unless you use dd to block copy your OS off to another spare drive, then install 2 [same size] drives, set up the bios raid, boot from the install cd and use dd to reinstall your OS onto the new mirror). Yes, you can mirror all partitions (/boot, /, /home& SWAP).
David, I guess this is not correct. When you enter the fakeraid BIOS you can make an array and choose 'copy' option. This will make the array and copy the content of disk1 to disk2.
This is only true for some bios's , some cards. It's not a given.
Or you can make the array without copying, then boot a live linux (eg knoppix) and use dd to copy disk1 to disk2.
It is not necessary to copy disk1 to disk3, make array with disks 1 and 2, and copy back the data from disk3 to the array. However I agree that it is the safest solution since you will have a complete backup.
This is almost always NOT true at all. When you tell the bios to assign the drive to an array, the bios uses some of the drives space to write raid metadata and that space becomes invisible to linux, whereas before you assign the drive to any array, linux has access to the entire drive. If you start with a non raid drive, dd it to another, and THEN tell the bios to use them both in a raid1 array, on most fakeraid bios's this will result in overwriting part of your filesystem with bios raid formatting data, which means corrupting, possibly entirely destroying destroying the entire filesystem. There are advantages to hardware raid. There are advantages to software raid. Fakeraid is "the worst of both worlds". You get all the disadvantages of software raid and all the disadvantages of hardware raid, and one teeny tiny little unnecessary advantage of hardware raid, which is just that it's possible to boot from the the array, don't need a non-raid drive to boot from. I've only booted from usb thumb drives for years so I happily make all drives fully software raid-whatever-raid-level-I-want. Even on a laptop where you can't leave a thumb drive plugged in all the time, but you had more than one hard drive which is still rare if no longer unheard of, you still don't need fakeraid. You just partition a small boot partition on each drive the same way, make those a raid1 array in fully regular software raid, and the bios can boot from either copy just fine without knowing that it's part of a raid1. Even some versions of Windows have software raid so even if you wanted to dual boot with Windows and you wanted Windows to have raid too, as long as it's any of the versions with dynamic disk you still don't need fakeraid. You'd need a laptop with more than one drive and Windows 2K/XP/Vista/7 Home to actually need fakeraid. And if you were dual booting Linux on that box you'd need dmraid in Linux. -- bkw -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org