[ale] Buwahahah!! Success!

[Charles Shapiro]

Heh heh.  I knew that you were an lvm Wizard. But I was determined not to
rope you into this.

I've actually got an old lvm root and old lvm swap partition on my Spinning
Rust drive.   I switched the swap over so as not to beat my poor little SSD
to bits ( tho at 32 gb I don't think I am actually using any swap).  I
could get rid of the old root partition and merge it into /home, but my
current /home is 432 gb and less than half filled. The /old_root is a big 9
gb.  Barely worth it IMNSHO, but I might get 'round to it just for the
edumacation value.  I fiddled with ext4 file system extension on the VM and
was properly impressed.

I've got a couple of metal parts on order to add to Piglet ( the ssd is
currently hanging on to the case by a single screw).  I kinda enjoy messing
with hardware.  This is the first mobo and processor I've bought new in a
long time. It's way overkill for my usage. But hey, I like having all that
computing muscle. Makes me think I am Badder than I really am. sensors(1)
shows everything loafing along at a maximum of 25C.

-- CHS

On Wed, Aug 30, 2023 at 8:47 PM Jim Kinney <jim.kinney at gmail.com> wrote:

> 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
>>
>>
>
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