Guest cosmiclint Posted August 13, 2007 Report Share Posted August 13, 2007 I am trying to set up a software RAID with three IDE drives. As it is apparently not a good idea to have two drives on the same IDE bus, I would like to use a Promises SATA 300 tx2plus - which has an Ultra ATA/133 Channel -to connect the third drive. After installing the card, Mandriva seems to detect it. lsmod |grep promise reports sata_promise 9604 0 libata 60620 2 sata_promise,sata_sil and the card shows up in the SATA section of the hardware manager in the Mandriva control center. But connecting an IDE drive to the controller seems to have no effect. ls -l /proc/ide only shows ide0 and ide1, and the drives connected to them. fdisk -l shows only the drives on ide0 & ide1. I don't have a SATA drive to test on the controller, so I don't know if it is only the IDE channel that is not working, or the card itself. I suspect I may be getting an IRQ conflict, but I am not sure how to go about trouble shooting this. I have tried searching for "install ide controller" +linux on Google, as well as this message board, but have not come across anything. If anyone can offer a suggestion I would greatly appreciate it. Quote Link to comment Share on other sites More sharing options...
scarecrow Posted August 13, 2007 Report Share Posted August 13, 2007 I don't think you can set a RAID array on disks lying at different controllers... just for disks plugged onto the same controller. Three years ago or so it was indeed unwise to connect two drives on the same bus, but this shouldn't be a problem anymore. I do not do it myself, but the only good reason is that I'm a tad too oldfashioned... :P Quote Link to comment Share on other sites More sharing options...
Guest cosmiclint Posted August 13, 2007 Report Share Posted August 13, 2007 Thank you for the response, scarecrow. I don't think you can set a RAID array on disks lying at different controllers... just for disks plugged onto the same controller. From the Software-RAID Howto: Linux RAID can work on most block devices. It doesn't matter whether you use IDE or SCSI devices, or a mixture. Also There are no other special requirements to the devices from which you build your RAID devices - this gives you a lot of freedom in designing your RAID solution. For example, you can build a RAID from a mix of IDE and SCSI devices, and you can even build a RAID from other RAID devices (this is useful for RAID-0+1, where you simply construct two RAID-1 devices from ordinary disks, and finally construct a RAID-0 device from those two RAID-1 devices). It doesn't say specifically that you can use more than one IDE controller, but I'm pretty sure it should work. Of course, I haven't managed to get that working yet, so I could be wrong ;) Three years ago or so it was indeed unwise to connect two drives on the same bus, but this shouldn't be a problem anymore. I do not do it myself, but the only good reason is that I'm a tad too oldfashioned... :P The problem with connecting two drives on the same IDE bus - as I understand it - is that one drive failing can cause the second drive on the bus to fail as well. This may not be an issue with newer drives, but I'd rather not risk it. Also, running two drives on the same bus degrades performance, as only one drive can be written to at a time. I'm using this RAID on my media server, and will be writing large audio and video files to it, so performance is an issue for me. I might just end up adding a SATA drive as the third drive, but it would be nice to get the IDE drive I already have working. Thanks again for the input. Quote Link to comment Share on other sites More sharing options...
Guest cosmiclint Posted August 20, 2007 Report Share Posted August 20, 2007 (edited) Well, if anyone cares, I've given up on the Promise controller and replaced one of the IDE drives with a SATA drive, which is what I should have done in the first place instead of trying to add the controller. For the benefit of anyone who needs to replace a drive in an array, just physically remove the drive you want to replace and install the new one. When you restart, the array will still work but will show as degraded. Use fdisk to create a partition on the new disc and set it to type fd Linux raid autodetect. Then (assuming your new partition is /dev/sdb1 and your array is /dev/md0) sudo mdadm /dev/md0 -a /dev/sdb1 You can keep track of the progress as it rebuilds with sudo mdadm -D /dev/md0 Don't forget to edit /etc/mdadm.conf and add the new drive to the list of devices. Edited August 20, 2007 by cosmiclint Quote Link to comment Share on other sites More sharing options...
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