[SOLVED] Trying to Dual Boot RHEL-5 with Win 7 on RAID 0

[Shamshir]

Hey guys!

I'm having a problem installing RHEL-5 on my system. I have Windows 7 installed so far on a Dell XPS workstation that came with hardware RAID 0. I have 2 x 500 gb hard drives. So I went in Win 7 and partitioned my disk to leave about 75 gb of unallocated space to install RHEL-5 on. I load the RHEL-5 DVD into my disk, restart my comp, and just follow installation steps. Use about 73 GB as an ext3 partition for the RHEL-5 and have about 2 GB reserved for swap space. RHEL-5 installs, and I'm all done. However, when I reboot the computer, the GRUB boot loader fails to load. I'm directly taken into Windows. How do I recover GRUB so I have the option of loading into RHEL-5?

I know I can remove the RAID 0 array and successfully get the GRUB to boot up, but I kind of like RAID and want to keep it. Thank you for your consideration.

[Rubberman]

Won't work (most likely) unless the RAID is purely hardware oriented and presents itself to the OS as a standard IDE, SCSI, SATA, or other drive type.

[devils casper]

Boot up from SuperGRUB CD/USB and check if it boots up RHEL-5 using its own GRUB.

[Shamshir]

Thanks for the reply guys.

Rubberman, my computer does have hardware RAID on the Mobo, though I don't know if it is "purely" hardware RAID. But ah, it's sad if it can't boot from RAID 0 . I had high hopes for it, especially since it actually recognized the RAID array. When I tried installing Ubuntu, it didn't even recognize the RAID array during partitioning and showed me as having 2 x 500GB HD's, so I did have some hopes about it.

Devils Casper, I tried your SuperGRUB idea. When I booted it up, it recognized Windows Vista BOOTMGR (strange, I didn't know 7 used Vista's boot loader) and "Other OS" (did not identify it as RHEL-5). When I hit enter on the "Other OS" it couldn't find the BOOTMGR file.

I'm taking this as a hint that I'm out of luck . I guess I could disable RAID on my PC (all files are backed up!) and get around the RAID that way. But alas, I bet you if I formatted my disk, recreated a new RAID array, and booted RHEL-5 only without windows then it would boot with no problems. Though since I'm new to the world of Linux it's not something I'd want to do.

[HROAdmin26]

When I tried installing Ubuntu, it didn't even recognize the RAID array during partitioning and showed me as having 2 x 500GB HD's, so I did have some hopes about it.

Then it's not hardware RAID. With real hardware RAID, the OS only sees the disk presented by the RAID controller.

But alas, I bet you if I formatted my disk, recreated a new RAID array, and booted RHEL-5 only without windows then it would boot with no problems.

I don't think so. I think the GRUB bootloader doesn't support booting from this onboard, software RAID device. Once the OS is loaded, it probably works fine. This is also why the SuperGRUB CD can't boot it either.

Because of these interlinked issues, the only option I can think of would be to boot Linux by adding an entry to the Windows bootloader. But the Win7 bootloader has changed, and I don't know how flexible it is now.

But I think this would still require:

1) Reinstalling the Windows bootloader
2) Reconfigure it to boot the "second partition" on the RAID (or wherever RHEL is installed.)

If that didn't work, I would blame booting from the onboard software RAID. At that point, I'd wipe the Linux partition, then reinstall RHEL using the generic SATA drive (so that each HDD is seen.) I'd install a software RAID in Linux using the md driver.

It all depends on how much you want to learn and how long you want to play with it.

RHEL is an enterprise Linux designed for servers. "Out of the box" support for desktops/laptops is not a priortiy.

[Shamshir]

Then it's not hardware RAID. With real hardware RAID, the OS only sees the disk presented by the RAID controller.



I don't think so. I think the GRUB bootloader doesn't support booting from this onboard, software RAID device. Once the OS is loaded, it probably works fine. This is also why the SuperGRUB CD can't boot it either.

Because of these interlinked issues, the only option I can think of would be to boot Linux by adding an entry to the Windows bootloader. But the Win7 bootloader has changed, and I don't know how flexible it is now.

But I think this would still require:

1) Reinstalling the Windows bootloader
2) Reconfigure it to boot the "second partition" on the RAID (or wherever RHEL is installed.)

If that didn't work, I would blame booting from the onboard software RAID. At that point, I'd wipe the Linux partition, then reinstall RHEL using the generic SATA drive (so that each HDD is seen.) I'd install a software RAID in Linux using the md driver.

It all depends on how much you want to learn and how long you want to play with it.

RHEL is an enterprise Linux designed for servers. "Out of the box" support for desktops/laptops is not a priortiy.

Hello HROAdmin. First off, thanks for the reply!

I definitely wouldn't mind learning, I'm actually very new to the world of Linux and am currently taking a Linux Admin and Networking course. I've been doing some awesome things that I though were never possible! Like changing the default run levels by editing the /etc/inittab folder and being able to set which kernel you'd like to load by editing the /boot/grub/grub.conf folder. It's been a blast so far! So if you have anything to teach, then I'm certainly all ears!

Just a few questions. Buy your reponse, am I correct to assume that if I did have true hardware raid installed on my Mobo, then I would have had no problems installing Linux distros that do not recognize software RAID arrays (like Ubuntu?).

Well, if I have to fiddle with the Windows boot loader, then so be it. I'm not averse to getting my system messed up (as I said, everything I need is backed-up) and Win 7 installs really fast anyways, so why not? I'm definitely game! Now I never used Vista (only XP before 7) and if I remember correctly in XP the boot loader for Windows was in boot.ini but for Vista and beyond it went into bcdedit.exe? I'll take a loot and see what I can do, but if you have any suggestions HROAdmin, I'm all ears! I'm not very knowledgeable in computers, I know a few bits and pieces here and there. But I can follow instructions!

Thanks again!

[HROAdmin26]

It sounds like you are well on your way.

am I correct to assume that if I did have true hardware raid installed on my Mobo, then I would have had no problems installing Linux distros that do not recognize software RAID arrays (like Ubuntu?)

As long as there is a Linux driver for the RAID controller, yes. Just like choosing a network card, you'll want to check the manufacturer's site and their track record supporting multiple OS'es. Thankfully, software RAID is never really an issue in Linux because of the md driver which supports software RAID in Linux across any harddrives.

A quick search for modifying the bootloader brought up this example about the Vista bootloader - it should be same/very similar to Win 7. I have only had to play with this new bootloader on Win2008 systems.

The tutorial talks about using NeoGrub + the menu.lst from the Linux install. Be careful, because menu.lst comes from Grub 1. Some newer distro's are using Grub 2. But RHEL will be Grub 1.

[Shamshir]

It sounds like you are well on your way.



As long as there is a Linux driver for the RAID controller, yes. Just like choosing a network card, you'll want to check the manufacturer's site and their track record supporting multiple OS'es. Thankfully, software RAID is never really an issue in Linux because of the md driver which supports software RAID in Linux across any harddrives.

A quick search for modifying the bootloader brought up this example[ about the Vista bootloader - it should be same/very similar to Win 7. I have only had to play with this new bootloader on Win2008 systems.

The tutorial talks about using NeoGrub + the menu.lst from the Linux install. Be careful, because menu.lst comes from Grub 1. Some newer distro's are using Grub 2. But RHEL will be Grub 1.

Ok thanks HROAdmin! This look like an opportunity to make some fireworks, so I'm excited! I'll give it a shot and see what I can do. Maybe it'll work!

As for the hardware RAID controllers... just did a search on Newegg and saw this:

ww.newegg.com/Product/Product.aspx?Item=N82E16816116042

Has the Linux drivers... now only if I had $329.99 to spare!

[Rubberman]

What HROAdmin26 said is very correct. I was misunderstood about Linux booting from Raid-0 (or any raid). My point was that multiple OS's may not play nicely together in this situation. As HROAdmin26 noted, it depends a lot upon the support of the RAID hardware vendor/supplier. In any case, I still don't like to us RAID for my boot volumes. I prefer a pluggable boot/system drive and keep a backup drive handy so if the boot drive fails, I can switch the backup in within seconds and have the system back up pdq. My experience with the efficacy of RAID has been mixed. Personally, I think the benefits are more psychological than actual.

All that aside, if your system supports RAID-0 (mirroring) in hardware (and the bios is properly configured), then the OS should not matter as it will appear to any OS as just a simple disc drive.

[Shamshir]

What HROAdmin26 said is very correct. I was misunderstood about Linux booting from Raid-0 (or any raid). My point was that multiple OS's may not play nicely together in this situation. As HROAdmin26 noted, it depends a lot upon the support of the RAID hardware vendor/supplier. In any case, I still don't like to us RAID for my boot volumes. I prefer a pluggable boot/system drive and keep a backup drive handy so if the boot drive fails, I can switch the backup in within seconds and have the system back up pdq. My experience with the efficacy of RAID has been mixed. Personally, I think the benefits are more psychological than actual.

All that aside, if your system supports RAID-0 (mirroring) in hardware (and the bios is properly configured), then the OS should not matter as it will appear to any OS as just a simple disc drive.

Thanks for the info!

I'm actually more trying to do this as a curiosity. Can I actually do it? It maybe something useful to know in the future if I can. Otherwise, I honestly don't need RAID 0 (which is striping btw, not mirroring). Apparently you get faster write speeds (I've heard of improvements from 90 mb/s to 140 mb/s using RAID-0) but I don't deal with über-large files and I'm not a hardcore gamer. Still, if I'm successful, then yay!

When I get the money, I'm somewhat tempted to build a new system with three or four solid state drives and put them in RAID 0.... now that's nirvana! . Ok I'm really j/k