Need help with Raid 5

[NibblesMctwitch]

Hello,


I have 3 4 TB hard drives and want to put them in a raid 5 configuration anyone know of any good recent tutorials?


Chuck

[antiX-Dave]

Software, or hardware, or done via the bios/ufi?

[m_pav]

If you have a hardware RAID, go ahead and partition as you wish because that will be transparent to the OS. If you want to use software RAID and your mobo BIOS supports it, the best option moving forward is, disable it, turn it off, don't let it do anything because it doesn't matter how the manufacturer puts it, it is a software RAID and it's tied to that one and only motherboard, not any other, therefore it's not transferable should you wish to do so in the future. Performance-wise, it'll be no different to a motherboard RAID so you have everything to gain and nothing to lose, plus, it might just be possible to build your own Live-USB using our snapshot tool to make rescuing your system just that little bit easier.

LAst time I used RAID was over 5 years ago and I haven't had the hardware to do it on since, laptops usually only have provision for 1 drive, so, I'm a little rusty.

There are posts on these forums related to RAID, I suggest you read through them first. google does a better job of searching the forum than our own search does, so simply search for MX Linux RAID and you'll find some interesting posts you may be able to follow to achieve your goal

[m_pav]

http://raider.sourceforge.net/

[JayM]

A software RAID can be created with mdadm (aavailable in MX Package Installer) following these instructions if you ignore any Ubuntu-specific stuff: https://www.digitalocean.com/community/ ... untu-16-04. I used them to create a RAID 0 out of two 120GB SSDs for increased capacity and slightly faster performance. It gave me 235GB after formatting as ext4. The mdadm commands are the same no matter what the distro.

If you want MX to be able to boot and run on your RAID that will require a hardware RAID controller card. Otherwise your system drive will need to be a single stand-alone drive, and the RAID used for extra storage of data. It may be possible to use your RAID as your /home partition as long as the mdadm RAID gets mounted early enough in the boot sequence, which I believe it does, but I haven't tested using a software RAID as /home.

[antiX-Dave]

If you want MX to be able to boot and run on your RAID that will require a hardware RAID controller card. Otherwise your system drive will need to be a single stand-alone drive, and the RAID used for extra storage of data. It may be possible to use your RAID as your /home partition as long as the mdadm RAID gets mounted early enough in the boot sequence, which I believe it does, but I haven't tested using a software RAID as /home.

Raid works fine as a /home mount. I have been using it for this for quite a while with a raid 1 set in desktops/servers. Though this is with antiX... Easiest to make your root partition with the home included. Boot into the fresh install and make the raid array on the other disks. Rsync the /home to the raid array. Edit /etc/fstab to point the the raid array for /home. Reboot.

Curious why do you say you cannot run MX on a raid setup? I have not tried. There would certainly be added complexity with initial setup using a common partition scheme and really 2 arrays (one level 1 for boot, another for the main raid), but it should be possible (Though I guess if your main array is level 1 you do not need to separate them). You could also use a sdcard/small hdd/usb/etc to start the boot if you were really stuck with building the boot partition into the array. I think there is (was?) a limitation in the gui installer which you should be able to get around by using the cli-installer. Unless the cli-installer limits where you can install instead of simply accepting what you type. I do not know how the MX versions differ from the antiX versions. Is there a limitation in initrd? Again I have not tried in MX so I am unsure of the limitation.

[NibblesMctwitch]

Thank's for all the replies.

This is for storage only and will be a software RAID, I had it in windows setup as a plex server.

Chuck

[JayM]

Curious why do you say you cannot run MX on a raid setup? I have not tried. There would certainly be added complexity with initial setup using a common partition scheme and really 2 arrays (one level 1 for boot, another for the main raid), but it should be possible (Though I guess if your main array is level 1 you do not need to separate them). You could also use a sdcard/small hdd/usb/etc to start the boot if you were really stuck with building the boot partition into the array. I think there is (was?) a limitation in the gui installer which you should be able to get around by using the cli-installer. Unless the cli-installer limits where you can install instead of simply accepting what you type. I do not know how the MX versions differ from the antiX versions. Is there a limitation in initrd? Again I have not tried in MX so I am unsure of the limitation.

I didn't try the cli installer, just the GUI. Maybe I'll try it again some day when I'm bored and have plenty of time to back everything up and make a new personal snapshot first. I do remember that the GUI installer at least didn't see my /dev/md0 as an installation destination, only the individual drives (dev/sda, /dev/sdb, etc.)

[esbeeb]

Don't use BTRFS for RAID 5 (that is to say, using BTRFS's in-built RAID 5 feature). It's not stable. It says so here:
Status: BTRFS Wiki: https://btrfs.wiki.kernel.org/index.php/Status

Maybe consider XFS?

[JayM]

BTW I confirmed yesterday that cli-installer can't install to a RAID0 either, even if I partitioned it ahead of time. Whenever I'd select /dev/md0p2 for the root partition it would reject it. I was expecting as much since mdadm is started as a service in /etc/init.d and if /etc is on a RAID, /etc can't be accessed until after /etc/init.d is accessed: catch-22. That's why you would need a hardware RAID controller, which sets up the RAID at the system/BIOS level so it's already there before an OS even comes into the picture.