Twenty Eight

My 28th year has been a great one. This year specifically, travel has picked up a lot, house renovations have greatly progressed, and lastly a few achievements I’m quite proud of.

Travel

Scuba diving the west coast of Costa Rica

Travel-wise there’s been several trips for both work and pleasure. In January, I got to visit Costa Rica – a perfect time to visit. I spent most of my time in Tamarindo, one of the more touristy towns on the west side of the country – the locals have nicknamed it “Tamagringo”. Some of the highlights were spending time on the beach, going scuba diving off the Catalina islands, and enjoying such a wide variety of food with great company.

In June, I had the opportunity for one of my teams at work to travel to Berlin! Given half the team was located in Ireland, it was time to pay them back by having us Canadians and Americans cross the Atlantic. Plus, this was my first time over in Europe! Some notable highlights of this trip were bonding with my team over German and Turkish food, a beautiful bike tour of the city, tasting a variety of German beers, and ripping around the city on scooters.

Lake Ontario

This summer was a fun kind of busy. The majority of the month of August was spent visiting my folks cottage, girlfriend’s folks’ places, and a few weddings, all the while mostly working at the same time – this flexibility is pretty freeing. We rented a car and sped off to spend time in places like Gravenhurst, Collingwood, Toronto, and Prince Edward County to enjoy nature, friends, family, wine, beer, and cycling. I’m sure we’ll do something similar again next summer, with the added benefit of using my own car.

In October, I combined a work trip to New York with a few extra days of pleasure. This trip was spent hitting up more of the niche places across the city, such as doing a tour around Brooklyn breweries, experiencing more of the restaurants and cocktail bars, and seeing one of my all-time favourite electronic artists: Flume.

Career

Cocktail making class at an offsite

As with every year, work has significantly changed in great ways. I received a promotion to Senior Development Manager, which cements my path on being a lead of leads. This year also saw a lot of great accomplishments and learnings such as growing my people leads, preparing one of my teams for reaching “feature complete” on a product, and getting even better at growing development teams into being self sufficient. One big growth opportunity I’m targeting now is to focus on strategic thinking to lead my engineering and product area for tackling our next big goals.

House

At home, I’ve been spending much of my time continuing on with home improvement, specifically a bathroom, bedroom, and kitchen reno – most of which I’ve been doing myself and reaching out to the pros when needed! It’s been fulfilling to go from knowing zero about tiling floors and walls to being pretty competent. Nothing like picking up another skill that pays off. Other proud moments were painting my girlfriend’s new place with the wealth of painting techniques and knowledge – it’s a great feeling to cut edges with ease and roll walls to get perfect, smooth coverage. My bias towards taking the time to do things right definitely showed on this and many other projects.

Cycling

Some of the best cycling adventures this year have been back up at the cottage in Gravenhurst, a botched go up the escarpment in Collingwood, through the wine region of Prince Edward County, and a loop around Amherst Island. Don’t tell the rental car company, but I strapped a $20 secondhand bike rack to the back of this beauty of a rental car to aid with a bunch of these adventures. A very entertaining purchase this year was a bike computer and power meter pedals. This exposed a ton of data I’ve dreamed about having for my outdoor cycling. Now I’m able to more consistently measure my actual wattage and fitness. This purchase made early on in the summer brought a lot of great and nerdy data for the rest of the year.

As always, Gravenhurst was classic – smooth, scenic routes through cottage county. On one occasion I had one of my best buddies up to the cottage with his bike as well. We rode into Gravenhurst and hit up the excellent Clear Lake Brewing Co. We also both got over our fear of riding without holding onto the handlebars 😂

Prince Edward County’s wine country roads make for picturesque cycling

When in Prince Edward County for a May 24 long weekend wine tasting trip with friends, we rented bikes from a local place in Hillier. What ensued for the rest of that day was beautiful bike rides from one winery to another, passing by vineyards and farmland. Over 15 km (if that) we hit up several wineries and one brewery for tastings. I’m not the biggest fan of the reds and whites that this region has to offer, but the last place on our ride, Traynor Family Vineyard, had the best tasting wines. That could have been the tasty pet-nat style, or just us all being blasted – probably both. To finish off that great last tasting, we had the best sunset ride back to our Airbnb. Shoutout to this bike shop for their great service!

Leading up to visiting Collingwood for a week, I knew there was a sizeable community of cyclists of all capabilities and had to scope out what great routes there were. On my first day grabbing coffee in town I started a conversation with a local cyclist and they very helpfully recommended some great routes and suggested avoiding some others. Collingwood has the Georgian Trail, an old railway bed turned gravel path running from its west side to Meaford – 34 kms in total. This was a great way to get some great views of Georgian Bay and stop by Blue Mountain for a coffee. One of the big trips I planned was taking many of the scenic backroads up the Niagara escarpment. This meant epic hills, great views, etc. Probably an hour in and most of the way up the 200m climb, I got a flat. A couple inner tubes later I figured out my tire had been the problem, and I called in for a rescue. I still need to go back and conquer the 70km loop I mapped out.

Amherst Island’s many fields and wind turbines

Amherst Island is a small island east of Prince Edward County. I was lucky enough to be invited out for a weekend by my girlfriend’s mom and her boyfriend who has a place on the island. One of the mornings was spent doing a 2 hour loop of the roads that mostly run the perimeter of the island. Rough gravel was a bit of a pain for my slick road bike tires, but pumping them up even more handled it without a problem. This ride brought beautiful scenery of Lake Ontario and sprawling farmland vistas.

What’s next?

Getting back into reading, and writing for that matter, would be a great throwback! My blog is definitely lacking posts, though I’m still amassing ideas for content, specifically around management.

I’m also looking forward to concluding most of the renovations that have been taking up most of my time to put towards more consistent cycling. I’d love to get into longer distances and more elevation during rides. Maybe that means doing a few loops in Gatineau Park now that it’s becoming quite a routine ride, or combining it with a couple dozen kms along some backroads.

As always, I’m looking forward to more trips. As I write this, I’m on my way to spend 10 days on the beautiful island of Kauai in Hawaii. 

Twenty seven

October 1st just passed yesterday. Another year in the pandemic, though I tried to make the best of it! Here’s the 27th edition of of my yearly reflections on what I’ve been up to, what I’ve achieved, and where I’ve grown. You can find previous years reflections since I’ve been Twenty, Twenty-one!, Twenty-Two, Twenty-Three!, Twenty-four!, Twenty Five, and Twenty Six.

I made the biggest purchase in my life to buy a duplex here in Ottawa’s Centretown neighbourhood. I’ve also become a lead of leads in my engineering organization. I’ve even had a few big accomplishments with my road cycling hobby thanks to a few friends.

One of my friends asked me about the high and lows of the year. After a bit of thinking, buying the house was definitely the height of the year. The low likely was not spending as much time as I usually would with family and friends either up at the cottage or travelling around. Let’s get in to a few of the highlights!

House

I bought a house, and moved in on the 5th of July! The landlord of the place I was renting previously was a seasoned real-estate agent. He shared some of his marketing materials with me sometime last year. With lots of people buying places in the country instead of the city to gain more space, the tradeoff wasn’t particularly worth it to me. Over a year into the pandemic and I approached my landlord to ask him if he’ll be my agent. He agreed and a month or two later of not many listings going up due to the lockdown, one place in Centretown meeting my criteria eventually showed up. I viewed it, ended up falling in love with it, and put in an offer for the place. As luck had it, my offer was accepted!

The dining room after some fresh paint and furniture

Over the past few months, most of my free time has been going towards making cosmetic improvements to the place, running ethernet cables through the walls, deep cleaning everything, buying new furniture, and starting the never-ending decorating journey. I’m quite glad that all of the DIY skills and confidence I’ve gained helping my family with their projects when growing up is helping me greatly now. Having extra time on my hands certainly helps as well!

I’m quite thankful for having an interior designer friend who’s been very handy when suggesting furniture pieces and paint colours. I definitely wouldn’t have as cool looking of a place without it! Another great friend has also lent me a number of tools to help with the handful of jobs I’ve been doing around the place.

I’m most excited about entertaining and enjoying the house when I’m not in DIY mode all the time. This Christmas should be a blast hosting my family, and there’s likely a few house parties I want to throw as things open up more. As long as I’m enjoying the space with others, I’ll be fulfilled.

The top floor deck with obligatory string lights

Career

Earlier this year I received a promotion to become a manager of managers! Yes, I’m in full Office Space-esque “What do you do here?” territory. Jokes aside, this has been incredibly exciting as I am now accountable for the people and product across a handful of teams. Very recently many of my previous responsibilities have been handed over to two fantastic people leads on my team. The conversations I’m having with them, some senior developers, and high growth individuals are very focused on helping them grow their careers and impact that they bring to the team, which has been quite fulfilling.

On the product side of things, a recent trend has evolved from “build extendable features for the long term” to “build self-service, or low-code features for the long term”. This is a neat observation and paradigm shift, which reflects on the development teams being more mature, and the need to build the right knobs and switches into the system to more easily enable the business to change how they work.

For a number of months, I was short a people lead for one of the teams and took on the extra load of performing all of the people management work until we hired on a permanent replacement. I had something like 17 half-hour weekly one on ones with everyone who normally reports to me, and every developer from the team that didn’t have a people lead. This took a crazy amount of time out of my schedule, but I loved the chaos and leaned into it. This was a great test of my time management, prioritization, and delegation skills. Since I wasn’t able to be involved in each team’s day to day, I heavily leaned on the seniors of each team to take ownership over the technical and product decisions. This worked out miraculously well, and was an amazing growth opportunity for these individuals to take on more ownership and make more decisions. Each team being in a mature enough state to not require my day to day involvement was key for me to focus on the more important people management side of things.

Growing of these teams also took precedence, as it periodically does every year. We grew the teams by several developers, hiring folks from Ireland, around Canada, and even the US. I still have to remind myself that we truly hire great people to work with, both professionally and socially.

Cycling

Happily cycling from the cottage to Bala in my Shopify-branded kit

Where to begin. One of the biggest forces that has helped push myself out of my comfort zone and see just how much cycling I can endure was thanks to a great amount of healthy competition with some friends. When the weather got cold, indoor cycling started, and a number of cyclists from work came together to do some virtual group rides. Three of us wanted to go further and ended up cycling multiple times a week. Over a number of months of seeing our cycling strength and endurance increase, we signed up for some very tough challenges in our virtual cycling app of choice, Zwift. Those challenges were:

  • The PRL Full route, consisting of 175 km, 2281 m of climbing. It took 7 hours!!!

I have to pause here, since going into this, we knew that this would be pushing our limits, and then some. Our times continuously riding were about 4 hours max. My cycling buddies and I were expecting this to be a 6-7 hour ride for us. Cycling for this long becomes quite the mind game along with the expected fatigue. As I shared above, my cycling buddies and I were able to finish it! I was seriously questioning why I enjoyed this whole cycling thing for a few days after that. To get over the pain and suffering of riding the same hilly route 11 times during the challenge, I forced myself a few days later to go ride it once more to get over my newfound loathing of it. It worked. I got over it. The best part about this challenge was that every other challenge paled in comparison since none were as challenging as this!

Otherwise here’s a few other notable achievements from doing all of the indoor cycling on Zwift:

From all of the cycling, the amount of power I could exert increased from 2020 to 2021 significantly! Some quick number crunching shows a 40-60% improvement, which is mind blowing!

2020 (lighter line) to 2021 (darker line) watts/kg power curve.

When the weather warmed up, there was a number of great adventures and achievements that were had:

One of the funnest hills to climb on the Forks of the Credit ride, this switchback was beautiful to take in

I can’t wait to see what I’ll get up to next year cycling-wise!

What’s next?

Well, there’s probably a decent amount of travel I’m looking forward to over the next year. Some already figured out such as a handful of business trips to hang with the teams, and an unknown amount of personal ones with friends and family that I’m most excited about.

Once the renovations and DIY around the house have settled down, figuring out what I’ll do with the other unit is on the list. Having a second source of income can only help set myself up more for the future.

Hopefully I’ll do some even bigger cycling trips, and get around to that bike camping I wanted to get around to this past summer. Buying a bike computer and power meter would help on these adventures and regular training too.

2022 is looking bright!

Binge-worthy podcasts discovered during the pandemic

Throughout 2020 I have listened to hundreds if not now thousands of hours worth of podcasts. Have I learned anything useful? Not really. Did it help keep me entertained through the pandemic? Hell yes.

This blog post complements another post I wrote a number of years ago which collected my favourite podcasts over technology, entertainment, and software development. This blog post focuses more on the different types of entertainment that are great for binging through while on a long road trip, while doing some chores, or desiring an escape from the day to day. Here are my reviews for a number of the most noteworthy podcasts that have kept me busy over the last year.

Not Another D&D Podcast

Not Another D&D Podcast paints an incredible adventure through its hundreds of hours of episodes. Dungeon Master Brian Murphy is an expert at storytelling while balancing the randomness of the game of Dungeons and Dragons. His ability to have such a wide array of voices for characters in the story complements the improv of players Jake Hurwitz, Emily Murphy, and Caldwell Tanner. The allure of the podcast is building up an adventure that the listener is highly invested in while joking around enough to not alienate the story.

I haven’t ever played a game of Dungeons and Dragons before, but got introduced to this podcast and the idea of D&D through listening to a hilarious holiday special episode that featured Amir Blumenfeld. I was hooked on this podcast ever since, and have gone so far to subscribe to this podcast’s Patreon primarily for the again-hilarious post-episode commentary.

The Adventure Zone

The McElroy family puts this excellent role-playing games show together. Brothers Justin, Travis, Griffin, and father Clint partake in a handful of sagas across Dungeon and Dragons, and other role-playing games. I particularly find their D&D seasons more entertaining than the rest. Their gameplay takes a bit more of an absurdist comedy approach compared to Not Another D&D Podcast, but the storytelling and character building is still maintained.

Some of the other off-season games they have played haven’t been as interesting to me. The game of D&D brings out more excitement and variety to the storytelling, keeping me on the edge of my seat, compared to the other games which involved a lot less game mechanics and leant more on the story being told.

Black Box Down

Gus and Chris walking through the unbelievable chain of events that go into many air flight incidents leaves you with a new appreciation for the safety of the flying industry. Each episode follows the timeline of events until disaster or rescue and then dives deep into the results of multi-year investigations that most of these flight disasters go through.

Gus is the primarily the one driving the show with storytelling and introducing new information, while Chris adds questions and commentary that many of us layman listeners would wonder about. The show keeps the listener tuned in solely based on what surprising or interesting new information will unfold for the current real-life story.

Some of my favourite episodes are the unbelievable fight between a hijacker and the flight crew aboard a FedEx flight, an interview with a plane crash survivor who believes they benefitted from the incident, and the recent Malaysian Airlines flight 370 which disappeared over the Indian Ocean.

Triforce!

This isn’t for everyone. Some poop jokes, a hint of political incorrectness, and banter about normal life from these three guys is surprisingly entertaining and definitely NSFW. Their day jobs are of streamers – those who play videogames for others to watch online. They convene weekly to catch up and make each other laugh over the mundane experiences they have, whats latest in the news, or the games they play.

To add to the uniqueness, many of the early episodes feature Pyrion’s original short stories of Bodega, a gunslinger in a futuristic galaxy. Scoffee, short for space coffee, is this universe’s version of our own coffee. This, and a handful of other original words add to the fictional world. After enough interest, Pyrion wrote a Bodega novel to connect together many of the storylines originally read during the podcast. I haven’t read it yet, but should eventually pick up a copy for myself.

Whenever I’m in the mood for a good laugh I know I can revisit a couple favourited episodes, or choose a random one if I’m feeling lucky. Some of those favourites are the absurdity of being at kids parties (#25), Pyrion and his sketchy neighbour (#40), and imagining a new and very NSFW gameshow (#89).

Notable mentions from this year

Deep Cover

An FBI agent retelling their experiences of going undercover and taking down drug lords? ’nuff said.

The Orange Tree

Not your typical murder mystery, The Orange Tree chronicles the brutal murder of Jennifer Cave, a student at Univeristy of Texas at Austin. The series is hosted by Haley Butler and Tinu Thomas who both attended the same university where the murder happened a decade earlier. They kept hearing about the infamous Orange Tree apartment complex from friends and the murder being in the news, which ultimately led the two to produce this show.

The format of the series consist of multiple interviews, retellings of news clips, court transcripts, and questioning to tell the story. Each episode does a great job at keeping you wanting to listen to the next episode based on a big reveal in the last few minutes of each episode.

Brainwashed

Revisionist History and Hardcore History

I’m no history enthusiast, but from listening to the Genghis Kahn series from the Hardcore History podcast helped change my view that history can be intriguing if told the right way. The same goes for a few episodes from Revisionist History’s telling of Curtis LeMay who was a prominent American Air Force General during World War II. I still have a vast amount of episodes to listen to from these two podcasts, but they will likely keep my interest for many hours.

That’s all for now

In the end, I wish there were more hours in the day to listen to more podcasts. Thankfully when I need a break from one, there’s another great podcast to start or pick back up.

ZFS snapshots in action

I recently had my laptop running Xubuntu 19.10 reach its end of life for security updates. I needed to upgrade to a newer version of Xubuntu to continue receiving the important updates. Luckily when I originally put Xubuntu 19.10 on this laptop, I installed the OS using ZFS as the filesystem – a feature new to the Ubuntu installer at that time. Thankfully ZFS proved itself as a great safety net for when the upgrade failed midway through the Xubuntu upgrade to 20.04 (the laptop abruptly turned off). But first, some background on ZFS snapshots.

ZFS Snapshots

One of the features not discussed in my previous article on ZFS was the powerful snapshotting features available to use. For any ZFS dataset (synonymous with a filesystem), snapshots can be created to mark a moment in time for all data stored within the dataset. These snapshots can be created or removed at any time, and will take up more storage space over time as files are added and removed after a snapshot has been taken. With a snapshot created, at any point in the future it’s possible to rollback to this snapshot, or go and read the data within it. Rolling back to a snapshot effectively erases anything that happened after that snapshot was taken. There are more advanced uses for snapshots that can be discovered in this great resource.

Right after I installed 19.10 a year ago, I created a snapshot to mark a clean install of Xubuntu in case I messed something up and needed to revert to a fresh new install. I haven’t yet needed to use this at all. Next up I’ll walk through my experience upgrading to 20.04 and using ZFS snapshots.

Taking ZFS Snapshots

Xubuntu 19.10 recently stopped receiving security updates, and therefore I needed to upgrade. The 20.04 version is Ubuntu’s long-term support (LTS) release, which provides a number of years of support and security updates – far greater than the non-LTS releases such as 19.10. Going into the upgrade I made sure to make a snapshot of all of the different datasets before performing the upgrade. From the Ars Technica article referenced eariler, the following command takes a recursive snapshot of all datasets that are part of the rpool:

$ zfs snapshot -r rpool@2020-upgrade

No output means that the command was successful. The following command then shows all of the different datasets that were snapshotted in the pool named rpool. If you’re following along, this may look a bit different for you. Ubuntu’s installer creates many different datasets for different directories, and two pools, one named rpool, and the other named bpool (not important for this article).

$ zfs list -rt snap rpool | grep 2020-upgrade
rpool@2020-upgrade                                                0B      -       96K  -
rpool/ROOT@2020-upgrade                                           0B      -       96K  -
rpool/ROOT/ubuntu_191r26@2020-upgrade                          1.98G      -     6.49G  -
rpool/ROOT/ubuntu_191r26/srv@2020-upgrade                         0B      -       96K  -
rpool/ROOT/ubuntu_191r26/usr@2020-upgrade                         0B      -       96K  -
rpool/ROOT/ubuntu_191r26/usr/local@2020-upgrade                  72K      -      112K  -
rpool/ROOT/ubuntu_191r26/var@2020-upgrade                         0B      -       96K  -
rpool/ROOT/ubuntu_191r26/var/games@2020-upgrade                   0B      -       96K  -
rpool/ROOT/ubuntu_191r26/var/lib@2020-upgrade                  35.8M      -     1.32G  -
rpool/ROOT/ubuntu_191r26/var/lib/AccountServices@2020-upgrade     0B      -       96K  -
rpool/ROOT/ubuntu_191r26/var/lib/NetworkManager@2020-upgrade    156K      -      284K  -
rpool/ROOT/ubuntu_191r26/var/lib/apt@2020-upgrade              6.41M      -     88.6M  -
rpool/ROOT/ubuntu_191r26/var/lib/dpkg@2020-upgrade             18.8M      -     40.8M  -
rpool/ROOT/ubuntu_191r26/var/log@2020-upgrade                  23.0M      -     1011M  -
rpool/ROOT/ubuntu_191r26/var/mail@2020-upgrade                    0B      -       96K  -
rpool/ROOT/ubuntu_191r26/var/snap@2020-upgrade                    8K      -      160K  -
rpool/ROOT/ubuntu_191r26/var/spool@2020-upgrade                  72K      -      112K  -
rpool/ROOT/ubuntu_191r26/var/www@2020-upgrade                     0B      -       96K  -
rpool/USERDATA@2020-upgrade                                       0B      -       96K  -
rpool/USERDATA/jon_ip6jrn@2020-upgrade                          396M      -     17.8G  -
rpool/USERDATA/root_ip6jrn@2020-upgrade                         404K      -     1.87M  -

Now that a snapshot was created, I could make any change to the system and be able to rollback to this snapshot, undoing any changes that were made after the snapshot.

Upgrading to 20.04

To perform the OS upgrade to 20.04, a sudo do-release-upgrade was entered, initiating the upgrade. Things were progressing well until the laptop’s battery unexpectedly ran out. Plugging in the power and starting the laptop back up, the login screen wasn’t showing up. Great. Thankfully there’s the little-known virtual tty consoles available a keyboard combo away for cases where you need a terminal but aren’t able to use the graphical window manager.

Now that I have a terminal on the laptop, poking around has shown that the upgrade was definitely interrupted midway through. Only a handful of packages were installed and many more needed to be installed and configured.

Instead of going on and trying to manually fix the failed upgrade, why not roll back to the ZFS snapshot taken just before the upgrade and restart the upgrade from this fresh state? This is what is shown next. With the open terminal, executing this command rolled back the system to the state taken at the 2020-upgrade snapshot.

$ sudo zfs list -rt snap rpool | grep 2020-upgrade | awk '{print $1}' | xargs -I% sudo zfs rollback -r %
$ reboot now

Performing a reboot right after executing this series of commands makes sure that the system is properly initialized from the 2020-upgrade snapshot’s state.

To get a better idea of what the above series of commands does, refer to this Ars Technica article.

And it Worked

After the reboot, the system came back up looking like it was exactly where the snapshot had been taken. I was able to proceed again with the upgrade to 20.04, this time leaving the laptop plugged in.

The safety net of ZFS snapshots proved itself during this experience. It can feel scary knowing that your data is on the line if things go wrong. Having a strong understanding of how ZFS and related systems work helped me get through this without making any unrecoverable mistakes. If you haven’t read it already, my previous article on ZFS takeaways includes many of the references I used to build a strong understanding of ZFS.

ZFS takeaways

ZFS is quite a feature rich filesystem. If you’re managing a number of hard drives or SSDs, the benefits of using ZFS are numerous. For example, ZFS offers a more powerful software-based RAID than normal hardware-based RAID. Snapshotting is a powerful feature for versioning and replicating data. Data consistency is built in and automatically makes sure all data continues to stay readable over time. The pool of drives can grow or shrink while being transparent to the filesystem above it. These are only a few of the powerful features gained from using ZFS. With this power comes a fair amount of initial overhead learning about how ZFS works. Though it’s worth it if you value flexibility and your data. Here’s a number of resources and tips I found useful as I learned and used ZFS over the past few months.

For a general overview of ZFS and more of its benefits, see this great ZFS 101 article on Ars Technica.

Testing out ZFS by using raw files

Throughout the Ars Technica article above, the author uses files on the filesystem instead of physical devices to test out different pool configurations. This is very handy to build up experience with using the different zpool and zfs commands. For example, I used this to get a feel for using the different types of vdevs and using the zpool remove command. A quick example is as follows:

$ for n in {1..4}; do truncate -s 1G /tmp/$n.raw; done
$ ls -lh /tmp/*.raw
-rw-rw-r-- 1 jon jon 1.0G Dec 21 17:09 /tmp/1.raw
-rw-rw-r-- 1 jon jon 1.0G Dec 21 17:09 /tmp/2.raw
-rw-rw-r-- 1 jon jon 1.0G Dec 21 17:09 /tmp/3.raw
-rw-rw-r-- 1 jon jon 1.0G Dec 21 17:09 /tmp/4.raw
$ sudo zpool create test mirror /tmp/1.raw /tmp/2.raw mirror /tmp/3.raw /tmp/4.raw
$ zpool status test
  pool: test
 state: ONLINE
  scan: none requested
config:

	NAME            STATE     READ WRITE CKSUM
	test            ONLINE       0     0     0
	  mirror-0      ONLINE       0     0     0
	    /tmp/1.raw  ONLINE       0     0     0
	    /tmp/2.raw  ONLINE       0     0     0
	  mirror-1      ONLINE       0     0     0
	    /tmp/3.raw  ONLINE       0     0     0
	    /tmp/4.raw  ONLINE       0     0     0

errors: No known data errors
$ sudo zpool remove test mirror-0
$ zpool status test
  pool: test
 state: ONLINE
  scan: none requested
remove: Removal of vdev 0 copied 38.5K in 0h0m, completed on Mon Dec 21 17:39:09 2020
    96 memory used for removed device mappings
config:

	NAME            STATE     READ WRITE CKSUM
	test            ONLINE       0     0     0
	  mirror-1      ONLINE       0     0     0
	    /tmp/3.raw  ONLINE       0     0     0
	    /tmp/4.raw  ONLINE       0     0     0

errors: No known data errors
$ sudo zpool destroy test

Here I use truncate to create four 1 GB sized empty files, then created a zpool named test with two mirror vdevs, using those four raw files. Then mirror-0 is removed, moving any blocks over to mirror-1. The pool is then finally destroyed.

Really understanding vdevs

Vdevs are a foundational part of using ZFS, and knowing what each vdev type accomplishes, and their strengths and weaknesses helps build confidence in keeping your data safe. This Reddit post on the ZFS subreddit goes into detail about many of these considerations. Again, in advance of making changes to a production ZFS pool, dry-running the changes on a test pool can provide more confidence for the changes to be made.

Adding and removing disks

One of the newer features allows removing only certain types of vdevs from a pool via the zpool remove command. This Reddit post and answer goes into some of the different potential scenarios. I did some thorough testing with a test pool of raw files before making any changes to my production pool. The zpool manpages mention the following about what can and can’t be removed:

Removes the specified device from the pool. This command supports removing hot spare, cache, log, and both mirrored and non-redundant primary top-level vdevs, including dedup and special vdevs. When the primary pool storage includes a top-level raidz vdev only hot spare, cache, and log devices can be removed.

I was amazed at the ability of being able to remove a vdev from a pool and have all data transparently moved over to the rest of the pool with the pool still online. One command moved terabytes of data and verified its integrity before removing the vdev.

Use different /dev/ references when creating pools

A small, but important tip when it comes to which /dev/ to use when adding devices to a production pool is to stick to using the device symlinks provided by /dev/disk/by-id/ or /dev/disk/by-path/ as they are less likely to change. Referencing drives directly like /dev/sdc can be more risky as these identifiers can change whenever hardware is added or removed from the system. The OpenZFS docs provide a great rundown on why this is recommended.

Other helpful resources

These were just a handful of my biggest takeaways of using ZFS over the past couple of months. A number of useful resources I’ve found along the way can be found here: