Greetings I have a simple Intel 865PERL motherboard and 1.8GHz processor test server w/ CentOS 4 on it. It was upgraded from 3.3 to 3.4 then "linux upgradeany" to 4.0. Ok, I started with one 40G PATA WD hard drive (/dev/hda) and just added a second identical drive on the slave controller and it is (/dev/hdc) I think /dev/hdb is the DVD/CDROM Here is the first drive /dev/hda on my test box. Filesystem 1K-blocks Used Available Use% Mounted on /dev/hda1 1004024 361112 591908 38% / /dev/hda6 5036284 35016 4745436 1% /home /dev/hda7 5036284 34920 4745532 1% /home/vpopmail none 517520 0 517520 0% /dev/shm /dev/hda5 5218040 32924 4920048 1% /tmp /dev/hda2 10080520 4143052 5425400 44% /usr /dev/hda3 10080520 280508 9287944 3% /var Disk /dev/hda: 40.0 GB, 40020664320 bytes 255 heads, 63 sectors/track, 4865 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/hda1 * 1 127 1020096 83 Linux /dev/hda2 128 1402 10241437+ 83 Linux /dev/hda3 1403 2677 10241437+ 83 Linux /dev/hda4 2678 4865 17575110 f W95 Ext'd (LBA) /dev/hda5 2678 3337 5301418+ 83 Linux /dev/hda6 3338 3974 5116671 83 Linux /dev/hda7 3975 4611 5116671 83 Linux /dev/hda8 4612 4865 2040223+ 82 Linux swap Ok, so... can I upgrade to mirroring on the fly? Is there a specific URL I should be learning from on this? When I get tired of this playpen and go to a fresh "test" install, what mirroring install facts and knowledge should I be following at that time please? In the very near future, I want to go to a large spin fast read/write hot swap RAID architecture. Sooooooooooo... Do you folks have any recommendations as to what URL's I should be looking at in the future for going to my long term goal of SATA RAID5 with an aftermarket controller like 3ware or other CentOS happy hardware RAID controllers? Thank you in advance for your time. - rh