On Thu, Aug 06, 2009 at 08:08:47PM -0400, Harold Pritchett (harold@xxxxxxx) wrote: > Mirrored Linux Mini How-to A few quick observations: > Install linux on two identical disk drives in such a way that the failure > of either of the drives will allow the system to be recovered without any > loss of data > > Both of the drives are partitioned exactly the same: > 1. 3 primary partitions > 2. Partition 1 - size - 1GB format as Linux Raid (fd) > 3. Partition 2 - size = real memory size, format as linux swap (82) > 4. Partition 3 = size = remainder of disk, format as linux raid (fd) If I read correctly, you are not only leaving swap out of lvm, you are not mirroring it at all - which would make the system crash if the swap disk breaks. Putting swap on lvm would also allow growing it easily as needed. Another point is that sometimes it is useful to have multiple partitions separately mirrored and then combined with lvm: it allows things like changing the raid configuration from two-disk raid1 to three-disk raid5 without moving data via backup and yet avoiding windows of vulnerability to single-disk failure during the transition. (Perhaps not common enough to be worth mentioning here, but I've found it useful.) > Define a raid 1 mirror named fd0 using the first partition on both drives > Define a raid 1 mirror named fd1 using the third partition of both drives Why "fd"? Sounds like floppy disks to me... why not md1 &c? (Please enlighten me if some raid tool normally uses fd.) > I'm from the old school. I believe in lots of partitions. So do I (indeed I'd add /var/tmp as a separate partition to your list), but it's independent of mirroring and not worth much space in a mirroring how-to (let alone mini how-to). Anyway, your method in all sounds rather too complicated (modern installers make mirroring during normal installation a breeze), and although doing it "the hard way" can be useful for learning purposes, I'd rather write a how-to using easier methods, possibly adding instructions for other tasks like how to handle broken disks, how to replace disks with bigger ones without reinstallation, how to add more disks, how to change raid configuration, &c. -- Tapani Tarvainen -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
