On Fri, May 13, 2022 at 8:04 AM Robert Citek <[email protected]> wrote:
> Admittedly, I haven't played with LVM in a while. But here's a nice > resource: > > > https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_logical_volumes/index > > this does look nice, but at first glance appears to be little more than a beginner's user guide. I need the advanced guide, the one that covers what to do when things go wrong. >From the output you posted, your md1 RAID6 looks like it's working fine, > i.e. no failed devices of the five that make up the RAID. yeah, it looks happy, but I'm not 100% convinced. who's to say that it didn't sync the new drive to the rest? I definitely did "shenanigans" to get it to sync and reassemble. but I don't know if there is a set of circumstances that could cause mdadm to do something screwy while looking like it's doing what I think it should be doing. However, from > the pvdisplay command, it does not look like you have any Physical Volumes > as part of an LVM. And without that, you have no LVM. It's possible that > you may have to "activate" the PVs or something to that effect, but my > memory is fuzzy on that. > # pvchange -axy 0 physical volumes changed / 0 physical volumes not changed so my question about that is, how does it know there's an LVM volume there? how can it be sure there's isn't one? I was hoping to find an equivalent to mdadm's --examine command. also, I'm only pretty sure this was an LVM volume. there is a small chance it might have been something else. which was the main question in my previous post: are there ways to identify a filesystem other than running file or strings on it? > However, before playing around with LVM, I'd strongly recommend making a > backup image of /dev/md1 if your data is important and you don't already > have a backup. If the data is not important, have at it and ignore the > rest of this message. > > I don't particularly care about the data, and I do have backups. this is largely an educational exercise. -wes
