[ale] Buwahahah!! Success!

[Jim Kinney]

Lvm is a total lifesaver!! You never know really how to partition a drive
so lvm can help expand a partition. On. The. Fly! Add a new drive or add a
new raid box and lvm says, sure, let's use that!

It also supports software raid which irritates the hardware purists with
deeper pockets that me. A software raid10 is cheap, fast, reliable, and if
I really need it, I can clone the box into a new mobo with some boot magic
and it resurrects the added blank drives in old and new boxes for me
without a pair of cards that cost more than the 4 new drives. Spinning rust
sata drives with 5 year warranties are totally worth it.

Yeah. Lvextend is a lifesaver. Lvreduce is awesome as long as the
filesystem is not xfs. Ext4 supports shrink. ZFS of course replaces ext4
and raid and lvm but does eat more CPU in Linux land. Pretty sure ZFS
borders on being a filesystem cult but the prophets have some really good
points. Maybe one day it'll get into the mainline kernel. Probably right
after gluster. 😁

I'm almost embarrassed to admit that I no longer fix my home gear. If it
pukes, it just gets replaced. Hardware is mostly pretty reliable (not gonna
discuss HPC/supercomputers running a hot tub style liquid cooling
solution). There's used Dell/Supermicro server gear in Suwanee data centers
that hits eBay. It's usually 5-7 years old and lasts another 3-5 years in
the home shop. 3 on the Supermicro, 5 on the Dell. But at $350 for a dual
CPU, 8-12 core, 64-128G ram, add your own hard drives, I'm happy.

I do need to kick the backups again. Long overdue for the bare metal
recovery of the entire backup system. Thanks for the reminder of "aging
backups".

On Wed, Aug 30, 2023, 5:36 PM Charles Shapiro <hooterpincher at gmail.com>
wrote:

> About three weeks ago piglet, my primary desktop computer, pooped out.
> Press the power button and the fans came on, but nothing else happened --
> no POST, no screen, like, Nuthin'.  Went through all the hardware
> troubleshooting I knew, carted it around to a couple of friends who are
> smarter than me, but never revived it. It was a Core I7 motherboard
> obtained surplus 5 years ago after a hard life as a server, so I reckon it
> was no big surprise it finally bit the dust.
>
> $500 or so and a couple of sessions at Decatur Makers later I'd replaced
> everything but the Mass Storage, the video card, and the case.  She would
> boot to the BIOS screen np. I could get the GRUB screen but no further --
> she'd would just Kernel Panic.  The new guts are a 12th gen Intel I9 on a
> Gigabyte Aorus Z690 gen 1.4 MB, so maybes that had something to do with it.
>
> Fortunately, I keep my OS on a 120 GB SSD, and my /home on a much larger
> Spinning Rust drive. So I knew that I wouldn't have to go back to my
> (shamefully aged) backups.  I installed Debian 12 on the SSD (up from
> Debian 11) and got her to boot ok.
>
> I configured my original install to use lvm without really understanding
> what that meant, so  my /home wouldn't actually, like, mount with a simple
> mount(8) command. Cue a deep-dive into lvm, helped along by an excellent
> tutorial ( https://linuxhandbook.com/lvm-guide/ ) which also let me delve
> into the Wonderful World of Vagrant.
>
> After groveling through all that mess, I did the following:
>
> * vgrename the old piglet-vg vgroup to piglet-home-vg ( using the UUID
> grabbed from vgdisplay so I was sure to rename the correct one)
> * vgchange -ay piglet-home-vg to 'activate' my renamed vgroup
> * vgscan --mknodes to fiddle the file system to recognize my new logical
> volumes
> * Verify that I could now mount(8) my piglet-home-vg/home lvolume on /mnt
> (Yay!)
> * systemctl set-default multi-user.target to bring the machine up with no
> GUI and log in as root
>  * Move the installed /home to /home-debian12-default ( in case I needed
> to grab some stuff from there to make the Debian 11 settings for Plasma
> work with Debian 12).  Make a new empty /home to serve as a mount point.
>   * Edit /etc/fstab to mount /dev/mapper/piglet--home--vg-home on /home
>   * systemctl set-default graphical.target to bring the machine back up
>
> Of course I still have a bunch of software to install and some stuff to
> bring back from my backup ( all my local apache stuff is gone for example).
> But it's really all over but the shouting.
>
> Fun Things I Learned:
>
>   * If you screw up an entry in /etc/fstab, Debian 12 will halt during the
> boot process when it tries to mount disks.  On some occasions, it'll
> attempt to mount your screw up for a while and time out after a minute and
> a half or so, but other times I think it just dies.  You can fix this by
> choosing Emergency Mode from the GRUB menu and fixing the bad edit in your
> /etc/fstab.  Or I suppose you could boot from your stick again if that
> rocks your sox.
>
>   * Debian 12 doesn't appear to let you mount an lvolume from fstab  by
> UUID. I could do this on my VM, which was running Ubuntu. On Debian you
> mount from /dev/mapper, which seems to be the Correct Way (at least that's
> the way shipped lvolumes are mounted).  There's some magic going on here
> that I still don't fully understand. Some of the hyphens in the /dev/mapper
> lvolume names are doubled, again for reasons which are inscrutable to me.
>
>   * Hardware can be Tricky.  If you don't plug in ALL the power connectors
> on your MB, it will simply refuse to start at all.  Then you will tear your
> hair out until you figure out the dumb misteak you made. And if you get
> checksum errors late in your install off a Stick, it means that the media
> is no good no more.
>
>    * vagrant and lvm are pretty way kewl.  Learning on a virtual machine
> let me hack away at lvm and other scary stuff (like parted(8) and mkfs(8) )
> break things, and still not disturb anything important on my personal
> machines.  Highly recommended.
>
> All in all a lot of fun.
>
> -- CHS
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.ale.org/pipermail/ale/attachments/20230830/9240d48c/attachment.htm>