how to start using RAID

[jancici]

I would like to use RAID0 in my desktop; I think that it can increase performance. so I decided to buy two same HDD and initialize RAID0 on them. I did start to read some articles about that, I am not sure about few thing so I would like to ask for help to understand. Thanks for your comments.

I have got MSI K8N Neo2 Platinium mainboard; It is supporting RAID functions.
I want to use two same SATA HDD.

1) question
do I need to create RAID0 array in BIOS?

2) these are steps how to move to raid0
a. konfigure kernel to support RAID0, it will not be modules
b. shutdown, plug new two HDD, start PC
c. create and configure RAID0
d. copy all data
e. update fstab
f. configure grub and restart
g. take out old HDD

2.c. : I would like to have some partitions. Let's say that I want these:
/
/home
/usr
/usr/local

so on each of HDD I will create same size partitions; after that I will have sda1 sda2 sd3 sd4 and sdb1 sdb2 sdb3 sdb4.
then I will create md0 from sda1 sdb1, md1 from sda2 sdb2 ...

is my thinking correct? if it is okay then 2.d. and 2.e. is easy

2.f. : I am not sure about booting process. There some command to RUN raid0 so I don;t understand how booting kernel can start on RAID0 array?

3) which packages should I install?

thanks for pointing me to right direction.

[Sadako]

There are two different ways to do this kind of raid in linux, the first is through hardware, if your motherboard supports it,
and the second is through software, using the kernels' md raid functionality.

You seem to be mixing elements of the two.

If you are using the hardware implementation, which is want you're probably looking for,
you shouldn't have to partition the two disks separately, the bios should present them as one disk which you would partition as you wish,
and the bootloader should work as normal.

With the kernel implementation, you would create an identical partition on each device for each raid volume.
Other than not needing any special hardware, the advantage of this is you can have a raid array together with normal partitons/filesystems on the same disk,
and if one disk is larger than others you can still use the extra space on the larger disk.
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[Phk]

there are nice tutorials around this forum, to simplify the process.

But managing and changing your Raid isn't just a one-liner

At first it will be hard.
At second it will be weird.
After the third try, it will be piece of cake. Trust me.

cheers
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[Mad Merlin]

Your "hardware" RAID is almost certainly fake RAID. The only benefit that fake RAID has over Linux software RAID is if you want to dual boot with other non-Linux OSes, using the same drives. Linux software RAID has a slew of advantages over fake RAID.
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[jancici]

I did look into manual of mainboard and I did find this in specifications: NV RAID (software) - so I think it's fake RAID.

I have only linux on my desktop so I will used linux software RAID. Do you think that this solution can increase performance?

- answer to my question 1) : NO
- I think that steps in point 2) are okay {maybe I forgot something or it will be little bit different, anyway I will do something }
- point 3 : I think that I need to install mdadm. Is there anything else?

my new question : which filesystem should I use? I mean if there is not problem to use XFS on raid

[beatryder]

I run a production server with software raid6 and it works great. I recommend following the guide on the gentoo wiki.
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[mbar]

[neysx]

http://www.gentoo.org/doc/en/gentoo-x86+raid+lvm2-quickinstall.xml

Hth