Partitions and RAID 1

SBFree · 11-20-2004, 11:32 AM

Hi -
I explored RH enough on an old P2 machine that it seemed like a new build was in order. I did a new build an would like to set up RAID 1. It has 2 IDE drives with the master smaller than the slave and I would like to put two partitions on the slave and have the first of the partitions be a RAID 1 mirror of the master drive. I would like some advice on partitioning and setting up the two drives to do this. I got to Disk Druid and felt unsure enough that I thought it would be better to look for help first. The drives are new and I would like to partition the entire first drive and an equal amount of the second to be a RAID 1 array. The remainder of the second drive can be used as one partition. Can I set up two physical drives to be a RAID 1 array? The first few passes kept telling me that my RAID array had to be on the same drive. The file structure is different and I'm not sure if I need mount points for the RAID array or what my mount point for the remaining portion of my second partition on the second drive should be. Sorry for being so long winded, I would rather get partioning done right the first time.

Thanks - Scott

Kreature · 11-20-2004, 12:55 PM

Not sure if anyof this anwsers your questions but this is how you would set it up :P

First make the raid partiions by using disk druid
choose new then choose software raid to make the new raid partition
make sure now that you select the drives you are using.
fill in the size for the partition
now that you have your raid partition created click the button RAID on disk druid
enter the mount point
your filesystem (ex. ext3)
now choose the RAID lvl 1
now choose the partitions that you want in the RAID array
and if you want these partitions formatted which will be most likely

let me know if this helped out at all

SBFree · 11-20-2004, 02:48 PM

Thanks for the reply. This is only my second Linux install. I was able to create the RAID 1 Array but wasn't sure what mount point to use. It seemed like I wanted "/" if the operating system and all user files were to be mirrored. Then it asked me to create a swap partition and I was uncertain if I should go back and make the RAID partion smaller on the first drive or just put the swap on the second drive which had tons of free space on it. I would like to use the remaining space on the second drive but am not sure where to mount it if it is not going to be part of the raid array. I was hoping to use it for video and audio media that didn't need to be backup up. Do I need a seperate swap partition? How big should it be? Is it ok to have it on the second drive? Any thoughts would be appreciated. Thanks. The first post was helpful. It's a lot of small steps in the newbie stage.
Scott

kenji1903 · 12-01-2004, 06:48 PM

Here is my fileserver setup, don't know if this helps though...

Code:

md0 -> hd[a/c]1 -> /boot
md1 -> hd[a/c]2 -> /home
md2 -> hd[a/c]3 -> /
swap -> ~2x(your amount of RAM)

From what i have read, the swap partition is similar to window's virtual memory; it's already RAID0. You do not have to create a RAID partition for swap.
Say you have 256MB of RAM, you can put 256MB into hda and the other 256MB into hdc, which totals up to be 512MB. (FYI, my CD-RW has taken hdb).

For RAID1 to work, say you have a 80GB hda and an 40GB hdc, you can only mirror up to 40GB. I tried this with 2 similar HDD, going to try HDD with different sizes today.

Please correct me if I'm wrong (as usual

), hope to get some feedback whether i am on the right track myself!

stormadvisor · 01-07-2005, 01:32 AM

Curious if you had gotten it going? What is the status? I am wanting to set up my on fileserver as well. i just don't know how to go about it.

kenji1903 · 01-07-2005, 03:21 AM

Yeah, some feed back would be nice

Electro · 01-07-2005, 04:18 AM

RAID 1 will not work well if the two hard drives are on the same channel. You have to place them on seperate channels. Make the swap on the bigger drive, but make sure its the first partition. You do not need swap be twice your system memory because that is overkill these days. Then you can make the RAID array. I would not put /var, /home, /tmp, and /boot on a RAID 1 setup because the RAID 1 array will always be writing and you will not get good reading performance that RAID 1 provides.

ReiserFS will be better than EXT3.

Swap can be RAID automatically if both swap partitions are the same priority and size. You do not need to setup a RAID partition for swap.

kenji1903 · 01-07-2005, 06:43 PM

Hi Electro,

Thanks for the info, I'll reduce my swap when I reformat the server, also will try out reiserfs

Um... /home contains most of the important data, is it advisable not to put that in the array?