Hi all! I recently built a cold storage server with three 1TB drives configured in RAID5 with LVM2. This is my first time working with LVM, so I'm a little bit overwhelmed by all its different commands. I have some questions:
- How do I verify that none of the drives are failing? This is easy in case of a catastrophic drive failure (running
lvchange -ay <volume group> will yell at you that it can't find a drive), but what about subtler cases?
- Do I ever need to manually resync logical volumes? Will LVM ever "ask" me to resync logical volumes in cases other than drive failure?
- Is there any periodic maintenance that I should do on the array, like running some sort of health check?
- Does my setup prevent me from data rot? What happens if a random bit flips on one of the hard drives? Will LVM be able to detect and correct it? Do I need to scan manually for data rot?
- LVM keeps yelling at me that it can't find
dmeventd. From what I understand, dmeventd doesn't do anything by itself, it's just a framework for different plugins. This is a cold storage server, meaning that I will only boot it up every once in a while, so I would rather perform all maintenance manually instead of delegating it to a daemon. Is it okay to not install dmeventd?
- Do I need to monitor SMART status manually, or does LVM do that automatically? If I have to do it manually, is there a command/script that will just tell me "yep, all good" or "nope, a drive is failing" as opposed to the somewhat overwhelming output of
smartctl -a?
- Do I need to run SMART self-tests periodically? How often? Long test or short test? Offline or online?
- The boot drive is an SSD separate from the raid array. Does LVM keep any configuration on the boot drive that I should back up?
Just to be extra clear: I'm not using mdadm. /proc/mdstat lists no active devices. I'm using the built-in raid5 feature in lvm2. I'm running the latest version of Alpine Linux, if that makes a difference.
Anyway, any help is greatly appreciated!
How I created the array:
pvcreate /dev/sda /dev/sdb /dev/sdc
vgcreate myvg /dev/sda /dev/sdb /dev/sdc
pvresize /dev/sda
pvresize /dev/sdb
pvresize /dev/sdc
lvcreate --type raid5 -L 50G -n vol1 myvg
lvcreate --type raid5 -L 300G -n vol2 myvg
lvcreate --type raid5 -l +100%FREE -n vol3 myvg
For education purposes, I also simulated a catastrophic drive failure by zeroing out one of the drives. My procedure to repair the array was as follows, which seemed to work correctly:
pvcreate /dev/sda
vgextend myvg /dev/sda
vgreduce --remove --force myvg
lvconvert --repair myvg/vol1
lvconvert --repair myvg/vol2
lvconvert --repair myvg/vol3
Teams is such a confusing app. To start off, what is it meant to be? A frontend for onedrive? A chat app? A videocall app? It's like microsoft's attemp to make their own everything app. What was wrong with Skype? Actually, Teams shows up as "skypeforlinux" (complete with a Skype icon) in Pavucontrol, so is the videocalling part of teams just a re-packaged skype? Why does the web version of teams have its own integrated Excel which is slightly different from standard web excel? It feels like the UI was specifically designed to mislead. There is a list of icons on the left that allow you to switch between different contexts in the app. The visual design makes it look like a set of radiobuttons, except clicking on some of them twice does a different action... There is a home screen, and then also a second SUPER HOME screen!? I can't even get angry it at for being a slow bloated jumble of spyware like the rest of microsoft's garbage (which it is), I just feel a sense of morbid fascination every time I'm forced to use it. It feels like an AI-generated app from a future where AI is much more capable but still utterly fails at understanding humans. It's the uncanny valley of user experience.