Hi, welcome to LQ forums.
It all depends on how he has set up your system. And Fedora 8 is very old, so you will have problems with support.
Since you have no Linux experience, and this is business environment, I suggest you pay some professional to install you CentOS 5.5 and set it up all with RAID. You could also do that by buying new hardware/PC so you get more RAM, more storage room and system supported (fixes) for next couple of years. CentOS is free of pay RHEL.
Until not long ago, Linux was not able to boot from partitions under RAID. That meant that /boot partition can not be mirrored, but the rest of the data can. If that is how system was set-up, then all of the data was mirrored but there is no GRUB/boot setup on the spare HDD. You would need to copy data from /boot partition to "/boot2" (/boot partition on spare HDD) and install GRUB on spare HDD MBR. This can all be done from working system, no need to unplug anything.
If you are not going to reinstall or swap your Fedora 8, then you could buy IDE DiskOnModule (512MB is enough) or buy/use separate HDD (new or used) and use it just for boot partition. If done properly, separate HDD would always boot the fist visible HDD no matter which one it is.
Take notice that RAID1 mirroring is not so much to give you FAST HDD swap, but to preserve you data. When you need to replace the failed HDD, you need to initialize the new HDD so system will recognize it as a spare for failed HDD. This can be done before the actual HDD fail (you can buy spare HDD even when you buy active ones), initialize it and keep it disconnected for latter use.
When I wrote "HDD" in this text, this can also refer to separate partitions since Linux software RAID system can use separate partitions on same HDD's for separate RAID arrays. At the same time, first partitions can be in RAID1-mirroring for /root partition, second (swap) partitions on both HDD's can be in RAID0-stripping for faster speed, third again RAID1 for data safekeeping and fort partitions can be out of the RAID system for larger capacity (storing non-essential data like music, movies and already backuped data).
As for synchronization, Linux software RAID should keep automatic sync, as soon as you plug in again disconnected HDD.
To see if you have synced data, run this command:
Output should be like this:
Code:
[root@kancelarija2 ~]# cat /proc/mdstat
Personalities : [raid1]
md2 : active raid1 sdb3[0] sda3[1]
212347072 blocks [2/2] [UU]
md3 : active raid1 sdb2[1] sda2[0]
31744320 blocks [2/2] [UU]
unused devices: <none>
[root@kancelarija2 ~]#
To show an example of different RAID systems on the same Linux system, compare all of my partitions with members above RAID partitions (md2=sdb3,sda3; md3=sdb2,sda3):
Code:
[root@kancelarija2 ~]# fdisk -l
Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 3965 31744440 fd Linux raid autodetect
/dev/sda3 3966 30401 212347170 fd Linux raid autodetect
Disk /dev/sdb: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 13 104391 83 Linux
/dev/sdb2 14 3965 31744440 fd Linux raid autodetect
/dev/sdb3 3966 30401 212347170 fd Linux raid autodetect
Disk /dev/sdc: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdc1 * 1 13 104391 83 Linux
/dev/sdc2 14 30407 244139805 83 Linux
/dev/sdc3 30408 60801 244139805 5 Extended
/dev/sdc5 30408 60801 244139773+ 83 Linux
Disk /dev/md3: 32.5 GB, 32506183680 bytes
2 heads, 4 sectors/track, 7936080 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk /dev/md3 doesn't contain a valid partition table
Disk /dev/md2: 217.4 GB, 217443401728 bytes
2 heads, 4 sectors/track, 53086768 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk /dev/md2 doesn't contain a valid partition table
[root@kancelarija2 ~]#
