Skip to main content

Lesson Learned On Logical Volume Management and RAID

The lesson is this; that just because you can doesn't mean you should.

I wiped off my RAID array and the data in it. It has around 300+G there, mostly downloaded, recoverable, and back-up'd to a CD/DVD content. I was trying to employ Logical Volume Management or LVM on an existing RAID array. After tackling RAID these couple of months, I figured I'm ready to face another monster. LVM is awesome because it can do partitioning, resizing, formatting, creating snapshots, while the system is online. You do not have to take it offline which to me is like magic.

Now that the data is gone, there really is no reason not to LVM the RAID. So after reinstalling my operating system (which is another long story), I reassemble RAID with:

#mdadm --assemble /dev/md0  /dev/sda  /dev/sdb  /dev/sdc

and checked the status of the array with:

#cat /proc/mdstat
or
#mdadm --detail /dev/md0

I checked the status of all the logical volumes with any of the following commands:

#pvdisplay     ;to check the physical volumes
#vgdisplay     ;to check the volume group
#lvdisplay      ;to check the logical volumes

I know that my home directory is going to need a lot of room for music and videos. I will have to create logical volumes for it to utilize the RAID which is now empty. I would leave some free space there for some flexibility.

To create logical volumes, I plan to extend the existing volume group first to include the newly assembled RAID. So I typed:

#vgextend ubuntu-vg /dev/md0

Then to create the logical volumes I need I typed:

#lvcreate -L size -n Musiclv ubuntu-vg
#mkfs.ext4 /dev/mapper/ubuntu-vg/Musiclv
#lvcreate -L size -n Videoslv ubuntu-vg
#mkfs.ext4 /dev/mapper/ubuntu-vg/Videoslv

I tested mounting them to home directory. I tried:

#mount /dev/mapper/ubuntu-vg/Musiclv /home/user/Music   ;since the Music folder already exist, I don't have to create them.
#mount /dev/mapper/ubuntu-vg/Videoslv /home/user/Videos     ;since the Videos folder already exist, I don't have to create them.

To check if they work, open the file manager, nautilus, and check out properties in particular. If you have trouble with permissions and ownerships of the files, then you should try:

#chmod 777 /home/user/Music
#chown user:user /home/user/Music
#chmod 777 /home/user/Videos
#chown user:user /home/user/Videos

These last series of commands will let you read and write your files and execute operations on them.

To make these changes more permanent so that even if you end your session and reboot they will stay, then we have to edit /etc/fstab file.

#gedit /etc/fstab

Put entries for each lv you created, something like:

                              
    filesystem       mount point        type         options        dump        pass

/dev/mapper/ubuntu-vg/Musiclv    /home/user/Music     ext4     defaults     0       0
/dev/mapper/ubuntu-vg/Videoslv   /home/user/Videos     ext4     defaults     0       0

As the names of the logical volumes imply, I plan to put music and videos on these folders.

Comments

Popular posts from this blog

Password Issues On Ubuntu Login

I found myself unable to enter my login credentials when prompted to do so in Ubuntu. I think I might have changed it then forget about it. I've been running the current session for more days than I should have. I forget. So what's the solution to my problem. How do I get in to my system now? It involved getting into the grub menu somehow. I am uncertain as to how to do that exactly in your system. So there's a couple of ways to do it (finger's crossed). When booting at system start, use the esc key or the shift key. The first one worked for me. The timing is key. Wait until the bios banner shows then hit the esc key once. I am using Ubuntu 22.04.4 here. I have a current version of grub. The grub menu will give you options and the one you want is: root. Yes you want root privileges to set the root password. It should give you a terminal access where you can issue commands. Type: #mount -rw -o -s remount / ==> this command mounts the filesyste...

New ZFS Pool And the New 4TB Hard Drive

I am using the new pool for my videos and music. Downloading them using my torrent client, transmission. The old pool is raidz2 and now I am using a raidz1 only. But and a big but I gained space of up to 4.5 TB.

2024 So Far

I have a feeling of moving earth or walking off my itchiness. The growing fat in my belly tells me I am failing on many occasions to give in to this urge. My eyes are blurred by morning glory. I remember my father having the same ritual in the morning. After his weak stroke, he couldn't speak much, just a grunt but he would demonstrate with hand how he liked to wash his face. The weather wasn't helping. It's been raining cats and dogs the past week. The province of Rizal was soaked and spilled volumes of water into the bay and Laguna lake. Our Caimito tree was cut to no more than 4 feet from the ground. It was towering above the corrugated sheet metal of our roof. Now it lay horizontal on the yard. I calculated it could be made into a whole table and chairs set by a talented carpenter artist. I showed Lino the two big pieces of trunk that could only be moved if cut by a power saw in place. The road widening project in San Mateo was in the middle stage. One side of the road ...