I don't know if this can even be done...

Currently I have a dell dimension, with a FastTrak TX2Plus RAID Controller Card. On which I have two SATA drives as RAID 0 (my boot drives). I am running kernel(s) 2.4.21 and 2.4.23, using the ft3xx.o driver available from Promise's website.

There is a new (open-source) driver as part of the libata patch: sata_promise.o. This lets linux see your raided drives separately. This is built into the 2.6 kernel. Obviously, I can't boot with this. It just tries to boot directly off the first drive (sda3) which effectively only contains half a filesystem!

I've been puzzling this in my head. How do I, and others in my position, upgrade to the 2.6 kernel when required? I think I'll need to set up software raid, creating /dev/md0 as a stripe of /dev/sda3 and /dev/sdb3, trouble is I can't do this in the old kernel (sdb3 doesn't exist), and I can't see my filesystem using the 2.6 kernel. Quite tricky!

Has anyone got ideas?

Thanks,

Erlend

It was a restriction that the boot stuff had to be on RAID 1. Striping (RAID 0) is faster for reading large files, but most people need to read large numbers of smaller files to load programmes or to serve files, so I recommend RAID 1 for the speed increase obtained by being able to read two files simultaneously.

Eh? Why's that? Does this mean I should create a separate parition for /boot and raid mirror that between sda4 and sdb4?

I've tried a few things to get the 2.6 kernel working with my raid0 partition (it is already raid0). One of them was to load the 2.4 kernel with the libata patch and once linux had loaded, modprobe sata_promise... it didn't work, kinda stalled my computer... probably didn't like the conflict of two drivers for one device!

I thought of installing SuSE Linux 9 on another computer, networking them, and using that compter's harddrive as root (I think you can do that, not sure tho?) so that I can boot.

Cheers,

Erlend

If you have the space, create a partition as RAID1. Make a filesystem on it. Copy your raid0 system (at least, /boot) to
the new partition. Adjust /etc/fstab and lilo or grub to show the new mount point for /boot.



From http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/custom-guide/ch-software-raid.html
I am puzzled. Have you been running 2.4 with hardware RAID0? To do that your kernel would need to have the driver compiled in. Since booting is rare with Linux , there is little penalty to
using RAID 1 for /BOOT. I always use software RAID 1 now, because it is simpler and discs are so cheap. It is also true that many (disc) heads are better than one.

Thanks for your replies.

I have the FastTrak Tx2Plus SATA RAID Controller Card. It is not actually hardware raid, it is software raid with (optional, primarily bios) hardware support. At the moment I am using it with kernel 2.4.21 (and 2.4.23) using the ft3xx.o driver as a module available from the Promise website. I use an initrd to boot (since driver is module).

The trouble is that this driver doesn't work with the 2.6 kernel. Instead, there is the sata_promise driver (which is actually now an option in the 2.6 kernel, and can be patched into older kernels). This is part of the libata patch. Basically this patch "removes the raid", each drive is seen as an individual drive, and so you are left to set up software (md) raid as you with. The trouble is, I already have a raid 0 array (which I'm not too keen on removing) on the disks, so when i boot in 2.6 the sata_promise driver loads, sees both disks (sda, sdb) and tries to boot off /dev/sda3. This fails, since sda3 only contains half the filesystem.

Cheers,

Erlend