Partitions Raid 10

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#1

I am installing a server on Suse 11 . I would like use a Raid 10. My motherboard (Asus P5QPRO) support RAID 10, so in BIOS I set RAID 10 and I am beginning to install Suse 11 but I am assailed by doubts about the partition of my 4 SATA.
In Custom partitioning for experts (in suse installation) I see:

/dev/mapper/isw_bbhgjighdb_Volume10 465.7GB BIOS RAID isw_bbhgjighdb_VOLUME10
/dev/sda 465.7GB ST3500320AS
/dev/sdb 465.7GB ST3500320AS
/dev/sdc 465.7GB ST3500320AS
/dev/sdd 465.7GB ST3500320AS

What are the right partitions for RAID 10? Thanks :slight_smile:

#2

If you have RAID at the motherboard/BIOS level, you need to set up everything there and it exposes the only the final configuration to the OS as normal drives. You don’t really do anything specific to the RAID at the OS level. As far as the OS is concerned, it simply sees them as normal drives and partitions.

Have you properly set up RAID10 at the BIOS level?

#3

Thanks syampillai for your reply.
In Intel Matrix Storage manager I set RAID 10 strip size 64 KB. It is very simply: it is only 1 click!
I see:
RAID VOLUME
ID 0- NAME VOLUME 10 - LEVEL RAID 10 (RAID 0-1) - STRIP 64 KB - SIZE 931.5 GB (I have 4 HD 500 GB) -STATUS NORMAL - BOOTABLE YES
PHYSICAL DISK my 4 HD size 465.7GB TYPE/STATUS member disk (0) for each disk .
Do I need to create the partition only on
/dev/mapper/isw_bbhgjighdb_Volume10 465.7GB BIOS RAID isw_bbhgjighdb_VOLUME10 ?
Do I need to create partition ext3 (and swap of course)?

#4

Once setup at the BIOS level, theoretically, you should see only one disk at the OS level. In your case, it is showing the RAID disk and the 4 physical disks. I am not familiar with Matrix Storage manager.

Anyway, install the OS on the RAID disk now, ignoring those physical disks /dev/sda, b, c and d.

Another issue I see the size it is showing. The RAID disk is shown in the BIOS having 931.5GB (which is correct) and in the OS, it has only 465.7 GB.

Partitions:
Sizing of partitions depends on your need. Do you want to set it up for a server environment?
ext3 is good. As a rule of thump, swap should be approximately double that of the main memory available.

#5

RAID 10 with a 64K chunk size is going to be a dog. I would recommend 256 or 512K chunks depending on your work load.

Also, you may want to consider using md devices (Software Raid) from within Linux, as if you change motherboards or yours breaks, your data may be questionably intact. With software RAID you can plug the drives in to another machine with at least as recent a kernel and retrieve your data. Also, many “BIOS” RAID solutions are just a firmware driven software solution of unknown performance and quality.

#6

Not many but all motherboard driven RAIDs are in fact software (and CPU) driven, that’s why you need drivers for that :slight_smile:

For real RAID you don’t need any drivers.

#7

They are still RAID, as they fit the definition; however they are not “hardware driven” as they are still highly CPU dependent for any calculations.

#8

Thanks for the answers! I have not crier if I can configure RAID 10 from Yast and I kindly explain to me how someone carries … I am really confused thanks

#9

Sorry for my previous post, it is not understandable…
I am trying to use suse 11 installation to set raid 10.
I understand how set 2 HD in raid 1 or in raid 0 but I don’t understand how I set 4 HD in raid 10 and I don’t understand how I must partitioning the 4 hdd: 2 HD in raid 1 with 3 partitions:
a - /boot
b - swap
c - /

and the other 2 HD in raid 1 with ???

thanks in advance for the help you give me

#10

In YaST to do it you have to use RAID 1 then RAID 0, however if you do it via command line it is much more flexible and can even use uneven numbered drives. Here’s a link on how to do that with decent settings:

RAID - MythTV

Also, you should not do a mirror of stripes, but rather, a stripe of mirrors.

Otherwise, you lose some of the robustness in the tolerance of failure. If you stripe first, a loss on the RAID 0 side will wipe out your data, so any disk loss will result in a failure of the set. If you lose any 2 disks you lose all your data that way. However, with a good RAID 10 you can lose up to 2 non adjacent drives.

To explain, let us assume you have 4 drives for your RAID 10. You have A, B, C and D

A and B become /dev/md0, a RAID 0
C and D become /dev/md1, a RAID 0

/dev/md0 and /dev/md1 become /dev/md2, a RAID 1, of 2 RAID 0, (10)

You lose drives A and D and now you have no data

Now, my scenario works like this:

A and B become /dev/md0, a RAID 1
C and D become /dev/md1, a RAID 1

/dev/md0 and /dev/md1 become /dev/md2, a RAID 0, of 2 RAID 1, (10)

You lose drive A and D

B contains all the data that A had. D contains all C had, you are still running.

#11

Many Thanks!!! I’ll try it :wink:

#12

Hi I’m setting up raid for the first time and I want to use raid 10. When I choose NAME VOLUME, then RAID. I can only choose Raid 0,1 or 5. So to setup raid 10 do I choose 2 drives on Raid 0 and two on Raid 1. is this how it works as there is no option for raid 10?

Cheers