almnck/assets/editorial/01edits/integrity-new-years-backups/new-years-backups.md

---
Author: Integrity Jones
Title: Looking Back Up
Published: 2024-01-01
--- 

To Old Danny, greetings:

The solar nights have barely stopped closing in, and we see even large language
models have been taking it easy for the winter. But for the faithful maintainer
of systems, there's still work to be done, here in the cooling embers of the year.

Now is a fine time of year to dust off your backup scripts, and see if they're
working as they should. An untested backup is no backup at all, said the wise
ghosts of the Scary Devil Monastery, and if we want to set the year off to its
best start, we should ensure we can pause, tear-down, and re-start it even at its lowest
points. 

When examining my backup and restore process, took the opportunity this year to
quadruple the size of my root partition on my server.

One last manual backup of the 256GiB SSD in my trusty server `boat` for the
sake of the old, and then an attempted restore for the sake of the new: to a
spare machine, `tub`, temporarily hosting a new, 1TiB SSD. If all goes well,
the restored backup in tub would have new room to grow, and I could swap
out that drive back into `boat` with minimal downtime.

That moment of hardware-swapping would mean that `boat` would have to be
shutdown and then restarted anew. Humans need their respite over the holiday break:
but should I have permitted my server the same indulgence? My plan accepted
that boat would be offline for, one hopes, a small slice of time.
There are more convoluted ways to ensure that none of my websites, file syncing, and
miscellaneous tools did not flicker, even for a moment.

I could have switched my DNS settings to the fresh clean `tub`, for instance,
while overwriting `boat`. Or perhaps just repurposed boat for gentler, less
demanding tasks, giving it the end-of-year gift of a well-deserved retirement,
and switched to `tub` a new year's responsibility of my hosting my main home
processes.

At the smallest scale, I do believe that uptime is overrated. We are surrounded
by tools bent into the shapes demanded by large tech companies, for whom site
reliability is their first commandment. 

But we are humans, not corporations. If even Homer nods, so can my home lab.
Christmas has its own folklore of visitors rebuffed, but hopefully my friends
have better things to do at this time than hit reload on my websites. Yes, a
personal webserver can go down for a few moments -- as long as it comes back up.

Which, with restored filing systems, is ever the question. Will the backup
truly come back up? A restored and rebooted machine may also be a time for
failure and death, just as, morbidly, we should note that human coronary deaths
seem positively correlated with the change of pace of the holidays.

I use the more positively-framed "Relax-And-Recover" (REAR), a recover system
from when sysadmins wrote shell code and /liked it/. REAR is a sprawling bash
scripts that runs your choice of backup code -- from rsync to borg-- over your
entire linux root, on a regular, cron-determined, basis. Having seen to that
prosaic task, it will also create minimal, bootable blob. The blob, stuffed
onto an USB drive, CD ROM, or networked drive, will boot into a minimal Linux,
 and  gently lead you through reconstructing a re-partitioning of a drive
 that will. At its end, the partition map on the machine you have booted
 will be exactly the same shape as your original machine. Then it will pull
 down your precious backups, and restore this drive to the precise state
 that your backups recalled it. A perfect, royal, restoration.

Younger readers born into our age of strong types and weak stomachs, may be
balking at the idea of entrusting restoration to a bunch of stringly-typed Bash
scripts. REAR's 20K(!) lines of shellcode intimate that it has reached the
edges of complexity beyond that you might think bashism can bear.

But this is /sysadmin/ shell code. That terrifying KLOC is
defensive, modular coding of the highest order. For the casual shell user,
REAR's operation is comprehensible, the failure modes anticipated, and
tweaks and errors are semi-obvious. REAR's authors emphasise "a relaxing
recovery", and ghosts of sysadminning past do not emphasise enhancing your
calm in those moments lightly.

I was never /not/ relaxed during my holiday restoration, but  I did
occasionally emit a high-pitched carol or two of concern. Firstly, I had REAR create ISO
files for burning onto a CD-ROM that I could restore from. CD stands for
"Cretaceous Disk". Even I have not used one of them in anger in over a decade.
Converting a bootable ISO into a bootable USB drive drive turned out to be
surprisingly tricky, and I can never remember how to do it. In the end I was
forced, humiliatingly, to read REAR's FAQ, where they recommended a heavy
utility, https://unetbootin.github.io/, for achieving this. In the future, I've
set REAR to output those bootable blobs as RAWDISK, which can be burned
(warmed?) onto a USB.

REAR's ecumenical acceptance of multiple backup programs introduces additional
complexity into its scripts. My use of borg backup tripped up the restore. REAR
scans executables that it plans to include on its rescue bootable blob, so it
can detect what libraries they need and copy those over. Sadly, the borg
executable can be either a binary executable (for which this works), or just a
Python script, whose demands REAR cannot fathom. This is undoubtedly a bug a
future REAR will fix, but in the meantime I just copied over the binary borg
into /usr/local/bin and used that instead of the Pythonic borg of the Debian
repos.

After those tweaks, tub was filled with the form of boat's Christmas past. I swapped
over the two drives, holding my breath, and losing the little SSD screw as
always (these plastic nubbin replacements tempted me in the fallout). Boat
wobbled and then, like a plucky North Sea veteran, bobbed back up.

Testing your recovery plans during your own end-of-year downtime and recovery
gives you a moment to peer at what has been, and prepare for the ups and downs
of the coming year. What will be the same? What will change? What parts of your
life can you simply hard link to the habits of the past? And what will you have
to incrementally add and integrate into your ever-evolving life?

Until next time, I am, 

~Integrity Mather