Hi, Karl, The very first thing you should mention is backing up the disk. Always a good idea, but especially so when formatting or partitioning disks. One mistake can spoil your whole day. Regards, Les H On Wed, 2007-08-15 at 14:34 -0600, Karl Larsen wrote: > I decided to write another paper that covers setting up a raid-1 > computer :-) As always it is a lot of work. Here is the start of it. > Please find errors and such and bring them to my attention. The paper is > about 1/3 complete. > > > A raid-1 configuration is defined as two Hard Drives (HD) having the > same computer software on each of them. If one HD fails the other will > continue to run and the computer will operate as if nothing had happened. > > Most of what is here is from an email of Jeffrey Ross who is a > member of the Fedora Users List. I have just used some examples and > re-ordering to suit my way of thinking. > > There are some special raid configuration software. One is "fdisk" > and with that you can make partitions that have the special fd > configuration. The other is called "mdadm" and it is written to be just > a raid technical assett. Read man mdadm to see how capable it is. > > Here is what you MUST do. > > 1. Your current HD and F7 partition is /dev/sda5 and your new HD will be > /dev/hdbx where x is a number from 1 to 7. The first thing to do is > decide how to lay out the many partitions it can look like this: > > /dev/sdb1 = /boot > /dev/sdb2 = /usr > /dev/sdb3 = swap > /dev/sdb4 = extended partition > /dev/sdb5 = /var > /dev/sdb6 = / > /dev/sdb7 = /home > > The partition size you find out by using "du -ch". For example to > see how big /usr must be in a Terminal cd /usr and there type $ du -ch. > On my F7 /usr is 3.4 Gbytes. So /dev/sdb2 should be 4 Gbytes or larger. > > Make the partitions with "fdisk". To do this you need to open a root > Terminal and use # fdisk /dev/sdb. If your /dev/sdb is a new HD it will > not show any partitions when you say p. On my old HD it shows this: > > Command (m for help): p > > Disk /dev/sdb: 160.0 GB, 160041885696 bytes > 255 heads, 63 sectors/track, 19457 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > > Device Boot Start End Blocks Id System > /dev/sdb1 * 1 1217 9775521 83 Linux > /dev/sdb2 1218 1945 5847660 83 Linux > /dev/sdb3 1946 1961 128520 82 Linux swap / Solaris > /dev/sdb4 1962 18534 133122622+ 5 Extended > /dev/sdb5 1962 7060 40957686 83 Linux > /dev/sdb6 7061 12159 40957686 83 Linux > /dev/sdb7 12160 18534 51207156 83 Linux > > Command (m for help): > > As you can see the HD has 160 GB and it has 5 Linux file systems and a > swap partition and /dev/sdb4 is an Extended partition. > > For our raid-1 work we want all partitions to be Linux raid > autodetect which you get with "fdisk" when you make a new partition. > Here is how it is done: > > Command (m for help): n > First cylinder (12160-18534, default 12160): > Using default value 12160 > Last cylinder or +size or +sizeM or +sizeK (12160-18534, default 18534): > 16000 > > Notice that I choose 16000 to end the partition. If you look the new > partition has 30 GB total space. > > /dev/sdb7 12160 16000 30852801 83 Linux > > The type of partition is wrong. We don't want Linux. We want raid and > that is done this way: > > Command (m for help): t > Partition number (1-7): 7 > Hex code (type L to list codes): l > Hex code (type L to list codes): fd > Changed system type of partition 7 to fd (Linux raid autodetect) > > Command (m for help): p > > Disk /dev/sdb: 160.0 GB, 160041885696 bytes > 255 heads, 63 sectors/track, 19457 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > > Device Boot Start End Blocks Id System > /dev/sdb1 * 1 1217 9775521 83 Linux > /dev/sdb2 1218 1945 5847660 83 Linux > /dev/sdb3 1946 1961 128520 82 Linux swap / Solaris > /dev/sdb4 1962 18534 133122622+ 5 Extended > /dev/sdb5 1962 7060 40957686 83 Linux > /dev/sdb6 7061 12159 40957686 83 Linux > /dev/sdb7 12160 16000 30852801 fd Linux raid > autodetect > > Command (m for help): > > To save what we have shown here type w as in write the new things. I > used q which means quit without saving. > > In our example we have to do the same thing for /dev/sdb1 through 7 > and it is easy to do and will not take long. Now our new HD is set to be > a raid-1 HD. > > 2. > Now back to the old HD. We need to make the raid partition numbers which > to make life simple will be the same as the new HD. We do this with > "mdadm" as follows: > > mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdb1 missing > mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sdb2 missing > mdadm --create /dev/md3 --level=1 --raid-devices=2 /dev/sdb3 missing > mdadm --create /dev/md5 --level=1 --raid-devices=2 /dev/sdb5 missing > mdadm --create /dev/md6 --level=1 --raid-devices=2 /dev/sdb6 missing > mdadm --create /dev/md7 --level=1 --raid-devices=2 /dev/sdb7 missing > > > -- > > Karl F. Larsen, AKA K5DI > Linux User > #450462 http://counter.li.org. >
