Ubuntu 11.10 installation using Software raid having issues installing grub

**mardibloke** · November 17th, 2011

Originally Posted by darkod

@mardibloke
For RAID0 you need to have a separate /boot partition outside the array. As far as I know it can't work otherwise. I guess it has to do with raid0 writing the data half on one disk and half on the other and the boot files can't handle that.

Thanks so much (had spent many hours on this), booted up now.

Attached screen shot shows what I was trying to achieve.

- --
Rod, UK

**darkod** · November 17th, 2011

Well I assumed raid0 of SSDs is for speed freaks.

It doesn't offer you any data protection and redundancy so as raid array it's pointless.

Just out of curiosity, what did you use for the benchmark? What is the best to use on ubuntu?

**mardibloke** · November 17th, 2011

Yes, I'm now backing up my complete /home daily to multiple locations

The included disk utility in Ubuntu is where that screen shot is from. I also played with hdparam :

Code:

rod@ubuntu:~$ sudo hdparm -t /dev/sda

/dev/sda:
 Timing buffered disk reads: 566 MB in  3.01 seconds = 188.18 MB/sec

rod@ubuntu:~$ sudo hdparm -t /dev/md1

/dev/md1:
 Timing buffered disk reads: 1586 MB in  3.00 seconds = 528.17 MB/sec
rod@ubuntu:~$

- --
Rod, UK

**darkod** · November 17th, 2011

How about some tool for random seek + R/W? This only shows sequential data which is OK, but the random is what matters more in everyday use. Especially as the disks start loading up the use will rarely be sequential.

**mardibloke** · November 17th, 2011

Sorry, not looked for a tool like that, and I'm now into why dual monitors not working with my Nvidia setup :/

- --
Rod, UK

**rasis** · November 30th, 2011

Hello, i think the problem is in the large hds.
This work for me:
1- Create a bios_grub partition, 1MB (or more) on each drive
2- Create partition for RAID as usually
3- Create software RAID 1 for all partitions but do not create a RAID with the bios_grub Partitions.

Excuse my poor english

**zatara1** · January 12th, 2012

Originally Posted by mardibloke

Thanks so much (had spent many hours on this), booted up now.

Attached screen shot shows what I was trying to achieve.

- --
Rod, UK

Do you know if this is similar for RAID 5? I am having problems getting RAID 5 to boot with the same error the person who started this thread did.

**punkybouy** · January 16th, 2012

I think what you really have here is a software raid device and without a driver Ubuntu will continue to see two drives at the end of the wire. You could see if the RAID card manufacturer has a Linux driver but you would still have to slipstream it into the install so the OS would see two disks as one. The only hardware RAID cards I know of that work out of the box with Ubuntu are Compaq SmartArray devices.