GPT Partion issues

robaiken
robaiken used Ask the Experts™
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Wise men i got another one for you.
GPT partition. Been trying to install linux on a raid 5 (four 1TB drives) but linux is not happy with this setup. I get all sorts of issues concerning the drive setup. Fedora and Ubuntu cant see the raid at all. Centos see it but complains about a GPT partion and cant install, blablabla.
Google showed me several ways i can remove the GPT partion but dont think it works.
I need help. It needs to be raid 5 because of the environment.
Any ideas anyone?
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Kerem ERSOYPresident

Commented:
Hi,

What is your configuration? Are you trying to install a hardware or software RAID? I guess your disks are not just regular SATA drives CentOS would be a better alternative as you've observed.


Cheers,
K:

Author

Commented:
Am trying to do a hardware raid, I thik i got an error when i tried software raid with Centos. IAm off to try again. What will you suggest
System Architect
Commented:
In order to have partitions larger than 2TB you cannot use the standard old days MBR , you need to use Intel's EFI/GPT partition tables.

GPT partitions is supported in Linux but for ubuntu you need to recompile the kernel , for CentOS its already compiled and ready.

I suggest that you create a small /boot and 20 GB / then you can use the GNU-Parted command to create the huge partition on the RAID and mount it to you system

Check this link

http://www.cyberciti.biz/tips/fdisk-unable-to-create-partition-greater-2tb.html

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Kerem ERSOYPresident
Commented:
Hi,

In fact this was what I thought when you say UBUNTU was unable to detect the drive. First of all you'll need to enter your BIOS RAID Setup during the boot. You'll need to create a RAID 5 volume and add all 4 disks to it (I assume the best configuration would  be a 3 volumes RAID-5 and 1 hot spare)

I'll suggest you to stick with CentOS since it is an Enterprise class OS it will detect virtually all RAID controllers available over Server Hardware.

Then you should start CD Setup. CentOS should not detect 4 volumes separately but should detect only one volume.  Then you'll continue setup without further configuring RAID and as if you have one single hard drive.

The GPT problem you2re having must be a side effect of you could not configure RAID and should not be observed anymore.

Also small_student pointed out you should not use MBR for volumes larger than 2 TB but since you're using a server and disks larger than 1 TB are not so popular with server I don't think this would apply to your case.

Cheers,
K.

Commented:
Added to the above, I'd recommend using Linux software RAID over any motherboard "hardware" RAID.

Author

Commented:
Ok heres what i have done. I got Five drives in my system, No hardware raid or anything like that. One of them i used for the os. Once the OS was up, it deteched the other four drives. I then set software raid up on those other four. Looks like its working great. So what happens if the HDD on whicch i have my OS dies? Replace and re-install. What happenes to data on my raid? I will have to setup raid again on the new OS which means i will lose my data right?

Author

Commented:
KeremE... Originally I setup hardware raid giving me a total of aba 2.xxTB thats when i started getting the GPT issues with Centos. Yes it does see one big 2.xxTB but i get errors. I guess thats when the MBR issue comes in.
Kerem ERSOYPresident

Commented:
When your OS disk dies and you setup it again and then you'd create a Software RAID Volume, and add your disks again and nothing has been lost.

BTW what errors you get when you have 2 TB H/W assisted RAID ? In no way you can use MBR for partitions over 2 TB so you'll need to go for GPT partitions.

Cheers,
K.


Author

Commented:
for hardware raid over 2TB, Linux report something similar to "Linux has detected a GPT partition blabla bla. Is this a GPT partition? I get a yes or no option. On either clicks, it say error then shows the GPT error message again. I think for now i will resolve to software raid and hope its as effective as Hardware raid.

Another issue and getting in relation to this GPT issue, I have set up hardware raid on a machine. Total space is about 1TB. Linux(Centos or Ubuntu) install fine but turns to freeze from time to time when in use.
This is a server installation we are talking about. Hardware is server based as well. When i do the installation withour HD raid, all is great. This obviously tells me something to do with the raid hardware but why? Why does it work sometimes and freezes sometimes?
Most Valuable Expert 2015

Commented:
This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.

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