Author Topic: [SOLVED]Cannot boot to any Software RAID setup  (Read 3727 times)

3dge14

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[SOLVED]Cannot boot to any Software RAID setup
« on: December 08, 2010, 05:29:50 pm »
I have built a new server (using Zentyal 2.0) to replace our Domain authenticating and primary file server.

The intent was to have a 3 disk (500g) setup with a RAID 5 partition for storage (/home)

It seems I've tried installing with every possible configuration (besides installing on 1 disk only) with the same outcome: "Gave up waiting for root device" "dev/mapper/****-ROOT does not exist. Dropping to a shell"

I am placing /boot on its own RAID1 partition at the beginning of the disks using ext3, I have tried including / in the RAID1 partition with /boot and tried including it with /home in the RAID5 partition with lvm.  Every setup I have tried has ended up with this same outcome. The grub bootloader is being installed on ALL disks, and all /boot partitions are being flagged as bootable.

What am I doing wrong? I tested having /boot and / on RAID1 with no problems on another machine. Should I just give up and put the OS and /boot on a SINGLE drive and /home on RAID5?
« Last Edit: January 18, 2011, 10:14:47 pm by 3dge14 »

RKB

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Re: Cannot boot to any Software RAID setup
« Reply #1 on: December 09, 2010, 12:42:07 am »
Hi,
Just you you know you are not alone. I have had the same issue, right now I am installing on one drive. Zentyal is not alone in this I have experienced these type of issues with a number of server distro's. Some distro's are close to prefect then up pops a 'little' problem that stops you getting that 100% operational server.

Thanks for reading this post.

Cheers

Ron

3dge14

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Re: Cannot boot to any Software RAID setup
« Reply #2 on: December 17, 2010, 10:34:58 pm »
Thanks for the response. After much blood, sweat and tears (about 25 installs), I have resolved the issue with one simple method.  I doubt this solves the issue, but it works around some kind of glitch or bug. 

I installed all the partitions (RAID1 and 5) at the end of each disk with about 50mb of free space at the beginning of the disk and now everything boots fine.

At the end of each disk(3) is a 2GB swap partition, then a 497.9GB partition for RAID5, and a 200Mb ext2 /boot partition in RAID1 (2 drives + 1 spare)

The RAID5 partition contains LVM with volumes for / and /home for storage.  Boots perfectly fine now.

RKB

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Re: Cannot boot to any Software RAID setup
« Reply #3 on: December 17, 2010, 11:20:58 pm »
Thanks for reply,
You are a lot more patient than me. I moved to SuSe 11.3 with ISPConf3

Cheers

Ron
Thanks for reading this post.

Cheers

Ron

Sam Graf

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Re: Cannot boot to any Software RAID setup
« Reply #4 on: December 18, 2010, 05:14:53 am »
Interestingly, according to The Official Ubuntu Server Book, Second Edition (for 10.04):
Quote
In the past there have been different limitations placed on Linux boot loaders.... Linux boot loaders sometimes couldn't boot if your root partition used a file system like XFS or if you used LVM or software RAID. A number of these issues have since been resolved, but some (such as booting from a RAID5 root partition) still remain. A common workaround, however, has been to create a small (64-128Mb should be enough) partition at the beginning of the disk for the /boot directory.


c4rdinal

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Re: Cannot boot to any Software RAID setup
« Reply #5 on: September 20, 2011, 05:08:28 am »
Thanks for reply,
You are a lot more patient than me. I moved to SuSe 11.3 with ISPConf3

Cheers

Ron

Hi Mate,

Did you use RAID for the swap partition?

Thanks

3dge14

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Re: [SOLVED]Cannot boot to any Software RAID setup
« Reply #6 on: September 20, 2011, 05:35:08 pm »
Thanks for reply,
You are a lot more patient than me. I moved to SuSe 11.3 with ISPConf3

Cheers

Ron

Hi Mate,

Did you use RAID for the swap partition?

Thanks

I assume you're asking me?

If so, then the answer is no. I didn't use swap in RAID, I created a 2GB swap partition at the end of each disk individually. These were also the first partitions I created since I went backwards (in order to leave some space at the beginning of the disk.)

normanp

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Re: [SOLVED]Cannot boot to any Software RAID setup
« Reply #7 on: September 20, 2011, 06:02:01 pm »
Just a thought - this may be the Ubuntu server installer bug where partitions on any individual 500GB physical disk must not total to exactly 500GB or over (eg 500.1GB total may be offered by the installer - say after creating 2GB swap you get offered 498.1GB - not OK) - its some miscalculation to do with total numbers of sectors or something. It is an obscure one that is avoided by say creating partitions that total eg 499GB.

Reinhold

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Re: Cannot boot to any Software RAID setup
« Reply #8 on: October 12, 2011, 09:21:54 pm »
HI 3dge

Quote from: 3dge14
...with the same outcome: "Gave up waiting for root device" "dev/mapper/****-ROOT does not exist. Dropping to a shell"
The RAID5 partition contains LVM with volumes for / and /home for storage.  Boots perfectly fine now.

It's obviously too late for you ...since you got it running... but the problem shows right in your above quote.
The automatic installer "forget's" to install lvm2
...so an automatic install would never get to the raid5 md
Should be solved in UBUNTU
... else just to a manual partitioning/install _and/or_ add lvm2 install when dropped to that shell

Quote
I am placing /boot on its own RAID1 partition at the beginning of the disks using ext3, I have tried including / in the RAID1 partition with /boot and tried including it with /home in the RAID5 partition with lvm.
For similar reasons you have to "/boot" from a (/dev/mdx), a raid1 
(no booting from (soft-)raid5, not without serious fiddling)...
...(best) location of root "/" is (imho) the raid5
...and most of use do this whole stuff to locate and protect "/home" in the raid5 anyhow ;-)

- There's no reason to use RAID for swap performance reasons. The kernel itself can stripe swapping on several devices...(if needed see software raid How-To)(otoh you can do)
- The offset or order of partitioning you did should (will!) have no influence. Linux Softraid "mdadm" is partition based and could care less where they are
- Note that you may have to check two things: i) is your bios set to boot from THAT raid1 disk ? ii) make partitions you want to be bootable - "bootable" (active, fdisk)

Regards
Reinhold



Reinhold

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Re: [SOLVED]Cannot boot to any Software RAID setup
« Reply #9 on: October 12, 2011, 09:30:57 pm »
Just a thought - this may be the Ubuntu server installer bug where partitions on any individual 500GB physical disk must not total to exactly 500GB or over (eg 500.1GB total may be offered by the installer - say after creating 2GB swap you get offered 498.1GB - not OK) - its some miscalculation to do with total numbers of sectors or something. It is an obscure one that is avoided by say creating partitions that total eg 499GB.

I am pretty sure this is not the case here... (...running several "2digit" TB servers here i.e. 10TB or more on 2 and 3TB drives and partitions)

Actually for zentyal this applies (imho)(MD or lvm2 or dm-crypt):
8EB for 64-bit CPUs on 2.6 kernels

...hard to realize physically A.D.2011  :D
Regards
Reinhold