Hi,

I am trying to triple boot rhel 7.2, centos 7 and windows 2012 r2 on dell t430 server with 3 hard drives, one for each os.

I am new to linux so i used easybcd and i get the same result - i can dual boot windows and whichever linux dist. mentioned before i installed last.

I cant get all three to work.

is there a way(using easybcd it's not a must - i dont mind editing config files) to have menu with all 3 os?

Thanks in advnce.

Are all three systems UEFI? If so, do they each have an EFI partition on their respective drives or are you using one EFI partition for all three?
If you have only one EFI partition, mount it to see if you have separate entries for all three systems.
Did you run grub-mkconfig from Red Hat or CentOS? Does it detect the other systems?

All three systems are bios not uefi.
After reading here i tried grub2-mkconfig -o /boot/grub2/grub.cfg.
It detected the other os and added it to a menu but does not boot the added item os, only the original os.

Which OS might be the original, Red Hat, CentOS?
Did it detect the other Linux as well as windows?
If it does not boot the second OS, what happens when you try? Nothing, black screen, error message, grub prompt, some other problem?
Also, for that to work with a Legacy/MBR system, you would need Grub2 code in the MBR and you said you were using EasyBCD. My recollection from using it years ago is that it would only boot one Linux system. That may not be the case now but if you have windows code in the MBR and use EasyBCD, none of the changes to Grub2 will matter.

Red Hat now, Centos in other tests - same result.

If you refer to command : grub2-mkconfig -o /boot/grub2/grub.cfg, itdidnt detected windows, only Two linux os.

If i am using the easybcd menu option Redhat boots Redhat, option centos boots Redhat as well.
If i am using bios menu to select Centos/Redhat drive as boot drive i am boting to Redhat or Centos witb no problems.

As for now it seems that Easybcd still boots only one Linux Dist.
I reinstalled Centos again without boot manager but the results are the same.
I didnt edited or added any code into the MBR but Easybcd might did that...
I dont have any problems not using Easybcd and edit any config files needed.
Also if it will be easier to config i can create raid 5 with all 3 hard drives and insall all Three os on one volume instesd of Three seperate drives.

update :
I reinstalled Centos on the 3rd drive without bootloader.
I tried grub2-mkconfig -o /boot/grub2/grub.cfg and now i had, like before another Two entries in the boot menu for Centos.
When i choose Centos i get "failed to start Switch Root" and i get into emergency mode shell command, typing exit here make the server freeze and i had to power off and on the server again.

EasyBCD is windows software so if you are using EasyBCD to boot the systems, what you have in Grub is going to be irrelevant. I haven't used EasyBCD in years because Grub/Grub2 just seem to be able to do more. If you have all these systems on separate drives, you might try installing Grub to the MBR of one of them and then running the grub-mkconfig command. All these changes to Grub are pointless if you are using EasyBCD as the bootloader. You might go to either the Red HAT or CentOS sites and find out specifically how to re-install Grub2 to the MBR. Usually the same method but different systems have minor changes. Take a look at the site below which has an explanation but not official CentOS/Red Hat so ...?

https://www.thegeekdiary.com/centos-...m-rescue-mode/

Thank you yancek for your help so far.

Your last suggestion didnt helped me, so lets try diefrent way...
Can you please provide me a guide for installong Redhat/Centos/Windows on 3 seperate disks or on big disk using grub2/grub only?

I don't know of any. Install windows to a separate drive including its boot code in the MBR.
Install CentOS to a separate drive including its Grub boot code in the MBR of that drive.
Install Red Hat to a separate drive including its Grub boot code in the MBR of that drive.

Decide which you want to use as the primary bootloader, Red Hat or CentOS, boot that drive by setting it to first boot priority in the BIOS. When booted to it, do the correct grub-mkconfig command, watch the outut and if you have the entries, test boot. If you are using Red Hat for anything more than testing you need to pay for support if you are currently not (?) after the 30 day test period.

You might try posting drive/partition information with the following commands run as root from CentOS/Red Hat.

Lower case Letter L in both commands.

What do you mean by :
Do i need to choose something other then normal installment of windows/centos/redhat?

I want the centos to be the primary bootloader, does it changes the command :
Which i'm going to use?

If you install windows on a Legacy/MBR system it will install boot code to the MBR of that drive, certainly if it is the only drive attached during install.

The default for Legacy Grub installs of the various Linux systems is to install boot code to the MBR, usually it will install to /dev/sda so if you are installing CentOS on sdb, you need to make that change. If you install Red Hat to sdc, you will need to change it to /dev/sdc as examples. Can't be any more specific as you did not post the output of the commands I suggested above indicating which OS was on which drive.

To make things simpler, i left the windows out for now and installed redhat on /dev/sda and centos on /dev/sdb.
Both installations boot normaly as a boot device.
Running grub2-mkconfig -o /boot/grub2/grub.cfg on the centos didnt made any change.
Running grub2-mkconfig -o /boot/grub2/grub.cfg on the redhat, added two Centos menue entries but as before,
trying to boot the centos gives "failed to start Switch Root" and i get into emergency mode shell command.

here are the commands you aske(from the redhat install) :
gparted :
-------------------------------------------------
Model: DELL PERC H730 Adp (scsi)
Disk /dev/sda: 299GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system Flags
1 1049kB 525MB 524MB primary xfs boot
2 525MB 299GB 299GB primary lvm


Model: DELL PERC H730 Adp (scsi)
Disk /dev/sdb: 299GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system Flags
1 1049kB 525MB 524MB primary xfs boot
2 525MB 299GB 299GB primary lvm




Model: DELL PERC H730 Adp (scsi)
Disk /dev/sdc: 299GB
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags:

Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/rhel_redhat72-home: 228GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 228GB 228GB xfs


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/centos_centos7-root: 53.7GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 53.7GB 53.7GB xfs


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/centos_centos7-swap: 16.8GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 16.8GB 16.8GB linux-swap(v1)


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/centos_centos7-home: 228GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 228GB 228GB xfs


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/rhel_redhat72-swap: 16.8GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 16.8GB 16.8GB linux-swap(v1)


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/rhel_redhat72-root: 53.7GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 53.7GB 53.7GB xfs
---------------------------------------------

fdisk :
----------------------------------------------

Disk /dev/sdb: 299.4 GB, 299439751168 bytes, 584843264 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000791cc

Device Boot Start End Blocks Id System
/dev/sdb1 * 2048 1026047 512000 83 Linux
/dev/sdb2 1026048 584843263 291908608 8e Linux LVM

Disk /dev/sdc: 299.4 GB, 299439751168 bytes, 584843264 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/sda: 299.4 GB, 299439751168 bytes, 584843264 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0002616c

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 584843263 291908608 8e Linux LVM

Disk /dev/mapper/rhel_redhat72-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/rhel_redhat72-swap: 16.8 GB, 16844324864 bytes, 32899072 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/rhel_redhat72-home: 228.3 GB, 228312743936 bytes, 445923328 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/centos_centos7-swap: 16.8 GB, 16844324864 bytes, 32899072 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/centos_centos7-home: 228.3 GB, 228312743936 bytes, 445923328 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/centos_centos7-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes