Installing CentOS7 with Raid 0

[yusha]

@"un4saken"


I have 3 hard disks for my client's server pc, But I am getting really confused how I can add all the hard disks to Raid 0 for the web-server on centos7, Any idea how can I do so... All I get is for centos 6... not getting any good article or video on CentOS7 Web-Server Customization on Software Raid 0..

 

[un4saken]

You can add a 3rd drive as raid 0, but you will not really see much difference.

If you ask me I would set the 3rd drive up as the backup. Go for 2 drives

http://weirdbricks.com/index.php/2014/08/23/installing-centos-7-on-my-old-gateway-gt5662/

 

[yusha]

@"un4saken"

Thanks for the link. I have tried as it says there. But having the following problem.

I have 3 hard disks First 250GB Second 1TB and Third 2TB
As I said I want to make the centos7 installation on software Raid 0, So I first select the 3 hard disks

From "Full disk summery and boot loader" at the bottom, I select the First HD which is 250 GB as the Boot Device

Now I clicked on Done and Deleted all the partition using " - " And clicked on "Click here to create them automatically" As you can see I had 3027.42 GB free of Total 3027.42 GB

After clicking on "Click here to create them automatically" Centos automatically creates /home as 2972.98 GB /boot as 500 MB / as 50 GB and swap as 3968 MB

But as I mentioned I wanted them to be in Raid 0 so I select /home and set that from Device Type Raid and Raid Level to Raid 0 and clicked on Update Settings. It did the Raid 0 with the 3 hard disks but the size of /home became 642.93GB

And when I un select the First disk which is 250GB from Device(s) Modify and just select the 2nd and 3rd drive

I got /home size as 1826.85 GB and 1145.94 GB as free.

Now again I am getting confused that how can I use the whole hard disks spaces as Raid 0 for the web server. Your help appreciated.

 

[smalpierre]

I'd install the OS on the 250g and get the client to buy another 2tb for the raid if it's primarily for data storage. If it's all about processing, I'd probably opt for a solid state drive instead. Anyway, I woudn't mismatch sizes in the raid. If I remember correctly it's going to size all the disks in the array to be equal to the smallest drive in the array, and they will perform at the rate of the slowest. I've mostly dealt with hardware raids though. Then again:

http://www.overclock.net/t/162862/possible-to-run-3-drives-in-raid-0

I don't have the answer to make what you want to happen work, but I don't think it will do what you think it will do. I could be wrong though - I've never tried it.

 

[yusha]

@"smalpierre" I've already did it on windows 8 using storage pool. All I want is just to apply the same thing on centos7.

 

[smalpierre]

Same computer? 3 different size drives? Did it show all the space? Maybe I'm thinking about a different raid level. I don't remember it's been a while. I think the last raid I had at home was a SCSI raid 5 - it was a while ago ardon:

 

[yusha]

@"smalpierre" Yeah same computer and same hard drives.. It shows all the spaces together in one volume. It was using software Raid 0.

 

[smalpierre]

Yeah, drive size shouldn't matter with raid0, it's just striping.

I've had a problem with large drives where windows won't recognize the whole thing. Shows a 200g as 130 but Linux read the whole thing just fine.

Maybe see if there's different software for the raid, or try a different flavor of Linux - might expose something you didn't think of that you could use with centos7?

 

[yusha]

@"smalpierre" It is now possible with window 8.1 and windwos server 2012 using storage spaces from control panel. you can see a video how windows storage spaces works from youtube. BTW, I've solved my problem 2 days ago on centos7 using LVM.

 

[smalpierre]

@"smalpierre" It is now possible with window 8.1 and windwos server 2012 using storage spaces from control panel. you can see a video how windows storage spaces works from youtube. BTW, I've solved my problem 2 days ago on centos7 using LVM.

Yesterday I was thinking about this, and it dawned on me that there's more than one way to set up partitions. I always use lvm if memory serves.

Glad you got it working, and thanks for posting the solution! I'm thinking about getting a new home server, and it will be runing the os from raid0 - my current home server will be turned into a nas - so that's good to know.

 

[tanaquil]

You should never user RAID 0.

This type of RAID was developped to offer greater performances as it will strip the data across all drives. The problem is when you los a single drive, you lose everything!

I recommand at least a RAID 5, that combine the stripping on 2 drives and a parity on the 3rd to procure a redundancy.

If it's performance you need, there is also RAID 10, the fastest RAID type, but you could also work with SSD drives, that never stopped to drop prices.

 

[yusha]

I think I knew that from a long time ago, though as I don't need any backup for the data yet, so why I choosed raid 0, and the servers are still running more than 2 years with raid 0 with no hard disks fail.. we're transferring more than a terabyte bandwidth daily from that server and its smooth.

 

[archomage]

[No message]

 

[amontes]

use mdadm

The first step is to put the disk and identifying it issuing fdisk -l to list all storage devices connected. You may get sda* something. Locate it and then use mdadm to build your array with software.