Adding Raid 1 Post Mageia Installation (A Query)

[manudenmage]

I wish to set up a RAID 1 array on two PHYSICAL disks, on the Remainder dev (to be exact, of 30.5Gb size) left over after setting up the root/boot and the swap partitions on the 74.5Gb sda disk, and a corresponding-sized dev on the second, or 74.5Gb sdb disk (pairing sda3 and sdb1, both of equal size... in SUSE, this can be done DURING installation, but SUSE doesn't like (function well with) my old PC's architecture, which is why I'm migrating to Mageia, except that there doesn't seem to be any way to do this in Mageia DURING installation... unless I'm mistaken).

So, I'm wondering if I can simply install Mageia 4 on sda1 (at 40Gb, with sda2 as the 4Gb Linux-swap partition), then, after the fact, use Konsole to install mdadm and proceed from there (following this procedure: https://raid.wiki.kernel.org/index.php/ ... up#RAID-1; or this one: http://www.dedoimedo.com/computers/linu ... ocId464958)?

Please make your responses as explicit as you would to a child - for that's what I am, both in Linux and in Mageia, despite any appearances to the contrary!

Thx,
manudenmage [Danish for "man without (a) mate", or, "man without parallel" : -) ... ye olde double entendre... though I'm born and bred American]
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[manudenmage]

Me again...

In case you're wondering why I would set up a RAID X array on only a tiny part/ single dev of my system, it is because the RAID 1 array is for my File Cabinet - this way, I can reinstall Mageia on the sda1 and keep my redundancy-protected RAID 1 File Cabinet intact.

Voilà
manudenmage

ps: Just to show you how much my Danish has slipped, English "man" is spelled "mand" in Danish, and normally "without parallel" (or "without equal") is "uden lige" in Danish. Um, to anyone interested in the arcane!
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[xboxboy]

Hi manudenmage.
I believe that can be done post install as you wish. I myself don't use mdadm (I have dmraid for a fake raid array that I setup post install, as I can't seem to get the install to like it). I don't think it will be terrible hard. It will take a little bit of messing around, but the wise folk here will be able to guide you. I have my root/boot/swap on one HDD and then 2 sets of 2 HDD's in raid 1 for the exact same reason you want too.

*And just remember, RAID1 isn't a true back up. (I said it before someone else gets in )

[manudenmage]

Thanks, xboxboy,

I'll give it a whirl, I believe that mdadm can be installed as part of the Mageia installation, so maybe as part of the installation process, I can take care of my mirroring file cabinet. And, yes, I realize that two disks can fail in quick series, destroying the data, or the one fails and one doesn't know about it until it is too late (in Windows, Belarc Advisor can be used to determine the health of one's physical disks, but maybe there's something equivalent in Linux??). Plus, I periodically keep a copy of everything on the one machine on the other (my main machine has a twin-boot, Windows plus (currently) open SUSE environment), but of course, in the extreme, extremely bad luck can destroy everything, but in that case, I believe that I would recognize that as my Appointment in Samarra http://en.wikipedia.org/wiki/Appointmen ... .27s_title!

Thx again!
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[madeye]

I have used mdraid on my server for a long time. And even though my server is not based on Mageia, the process to set up a raid is the same. I have always had good results following https://wiki.archlinux.org/index.php/RAID when I needed to build a raid.
A somewhat deeper explanation can be found at http://download.boulder.ibm.com/ibmdl/pub/software/dw/library/os-ltc-filesystems/Linux-Software-RAID-Tutorial.pdf
Although it is a bit dated it's still good reading.

And one last thing. (Even though it's already been mentioned). Raid is not a substitute for making backups! I learned that the hard way when my raid controller broke in a way that made it write garbage to all my disks! That's why I have a backup script running via cron to prevent that from happening again.

If you setup email alerts for mdadm, then you will be notified if there are problems with the raid. Likewise you can use smartmontools to monitor the harddrives themselves. At least the drives that have S.M.A.R.T.