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I am runngin Slackware 11.0 with a 2.4 kernel. I have 3 identical SATA drives. I put the OS on the first one and want to set up RAID0 on the remaining two. I managed to get the RAID array going manually using the mkraid and mount commands but when I reboot I get an error like "invalid raid superblock magic". Do I need a RAM disk? Why would it work at the command line but not when booting?
You don't need a RAM disk if you already have everything you need to boot up compiled into the kernel as in "y" instead of "m". Like your filesystem and raid stuff.
It sounds like you're installing a different kernel from the kernel you are booting with for the install. Which means you should install the one that you're booting with so it has the same capabilities when you reboot.
Well, let me ask you specifically since I'm not sure...
Are you running mkraid from an install CD or a boot floppy? In other words, what kernel are you using at the time you run mkraid and such? When you install Slackware you can install any kernel you want, but it's often a good rule of thumb to install the *same* kernel that you used *during* the install because it has already proven itself capable of seeing your hardware and booting your system.
For some reason your boot kernel is *not* capable of seeing the raid partition because the module hasn't been loaded in time during the boot process or because that support was never compiled into the kernel in the first place. The key here is to install a kernel that has the proper drivers you need. I would recommend the huge 2.6 kernel as it seems to have everything already in it.
I'm using raid 1 and that stock kernel worked for me. In the past I've had to roll my own kernels to get everything I wanted. That doesn't seem necessary with huge 2.6 anymore... at least I haven't needed anything it doesn't have yet ;-)
Not to hijack the thread, but if you are talking about running RAID0. The two reasons I am aware of for running RAID0 is to either get a larger mount or to improve write/read performance to this area.
If performance is what you are looking for running RAID in software would obviously cut any perfromance gain by striping. In both instances I personally would be running RAID in hardware via a RAID capable SATA PCI / PCI Express card. They are running as low as $20 these days. I found a few to pick from at tigerdirect.com.
May not be what you are looking for but possibly an easy fix you overlooked. But it could possibly add another problem, finding support for the card in the kernel or elsewhere.
I don't disagree with anything you are saying, but mr_scary still has the same problem. Unless his kernel *happens* to support the raid card out of the box, he still has to either roll his own kernel or find another one. Slackware has kernels that *should* work. One of *those* should be installed like huge 2.6. Getting a raid card would just be icing on the cake, but certainly not necessary. I, for one, would never run raid 0 because I think hard drives are too unreliable. I burn one up every 3 to 6 months. More hard drives compounds your exposure when they are not redundant. In striping if you lose one, everything is hosed. But... I digress...
Hopefully, we'll get your stuff working. Let us know if there is anything else we can do to help;-)