Adding A SW Array To Existing Setup

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EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/08 23:17:59

Hello, I have 8 drives (only 2 installed) and would like to add the other 6 to a raid 5 SW array.

Currently I have 2 SSD drives that are 128gb with centos 7 installed.

The other 6 drives I have just physically installed. I do not have a gui (command line only). The 6 new drives are also completely empty.

I was reading this tutorial http://zackreed.me/articles/48-adding-a ... dadm-array but it does not show how to add the drives in the raid 5 config.

Any help is greatly appreciated.

gerald_clark
Posts: 10642
Joined: 2005/08/05 15:19:54
Location: Northern Illinois, USA

Re: Adding A SW Array To Existing Setup

Post by gerald_clark » 2014/11/08 23:53:19

Don't do RAID 5. Do RAID 10.

EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Re: Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/09 00:12:52

gerald_clark wrote:Don't do RAID 5. Do RAID 10.
That takes up 2x as much space which I need.

So how do I add these drives to a SW raid?


EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Re: Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/09 00:42:14

Thanks.

what does the /dev/md0 stand for? since i already have a raid 1 for my OS drives does that mean that i need to use /dev/md1

Code: Select all

mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --spare-devices=1


Also if i type lsblk

it gives me
sdc
-sdc1 128M
-sdc2 3.6TB
sdd
-sdd1 128M
-sdd2 3.6TB
etc

do I need to erase these drives first? What created that 128MB partition? Drives are brand new.

gerald_clark
Posts: 10642
Joined: 2005/08/05 15:19:54
Location: Northern Illinois, USA

Re: Adding A SW Array To Existing Setup

Post by gerald_clark » 2014/11/09 01:01:02

If you want to use software RAID, you need to read and understand how it works.
I'm not going to give you step-by-step instructions, as they will not help you when you have problems later.
If you don't understand it, don't use it.
Again, don't use RAID 5.

EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Re: Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/09 01:23:56

Honestly I can read all day but this is actually the way I learn (actually doing it)

I will continue reading but in the mean time maybe someone else can help with the setup.

Also I will use raid 10 with more drives. Thanks for that advice/link

EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Re: Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/09 05:16:59

i did

Code: Select all

mdadm --create --verbose /dev/md1 --level=10 --raid-devices=6 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1
when i do

Code: Select all

mkfs.ext4 /dev/md1

Code: Select all

mount /dev/md1 /mnt 
I get a warning that says

/dev/md1 alignment is offset by 3072 bytes.
This may result in very poor performance, (re)-partitioning suggested.

What does his mean?
Last edited by EverydayDiesel on 2014/11/09 06:19:58, edited 1 time in total.

EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Re: Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/09 06:10:23

in case anyone else needs help here is how I formatted disks

Code: Select all

$ parted /dev/sda
(parted) mklabel gpt
(parted) unit TB
(parted) mkpart primary 0.00TB 4.00TB
(parted) name 1 media
(parted) print
number     start     end     size file     system     name flags
1    0.00TB    4.00TB    4.00TB        media
(parted) quit
then formatting each disk

Code: Select all

mkfs.ext4 /dev/sdc

EverydayDiesel
Posts: 51
Joined: 2013/08/11 15:51:42

Re: Adding A SW Array To Existing Setup

Post by EverydayDiesel » 2014/11/15 19:20:38

I think I have gotten close but after a week I have still not been successful. Well if a software raid is not the best choice can someone tell me what cables I need to combine these

case and mb
http://www.supermicro.com/products/syst ... -AR12L.cfm

hard ware raid
http://www.supermicro.com/products/acce ... P-H8iR.cfm

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