Monthly Archives: January 2022

ZFS compression is so good that it cost me 2 hours

So we have this build machine (build0) where we build FreeBSD in Jails and then we mount the src and obj dirs via NFS or we sync them using rsync to destinations so we can run make installworld on not-so-powerful servers.

Couple of days ago we had a network issue at the data center, the switches crashed and we had to reboot them. Turns out I was running rsync on one of our servers, so I decided to make sure that the files were copied.

Like a lazy sysadmin, I run the following commands on both the build0 server, as well as the remote host.

root@build0:~ # du -h -d 0 /usr/local/jails/f130/usr/obj/
 13G    /usr/local/jails/f130/usr/obj/

root@illuriasecurity:~ # du -h -d 0 /usr/obj/
5.5G    /usr/obj/

Hmm, maybe files were not copied properly? So I remove the obj dir and I rsync again.

Looks like the size is 5.5G AGAIN!

So I do a little bit of piping!

root@build0:/usr/local/jails/f130/usr/obj # find . | sort > /tmp/obj_build0.txt

root@illuriasecurity:/usr/obj # find . | sort > /tmp/obj.txt

zvartnots:~ $ scp illuria:/tmp/obj.txt  /tmp/
zvartnots:~ $ scp build0:/tmp/obj_build0.txt /tmp/

zvartnots:~ $ diff /tmp/obj.txt /tmp/obj_build0.txt

Um, no difference?

Looks like the size reported by du was… confusing?

Okay, let’s check the manual of du(1):

     -A		Display the apparent size instead of the disk usage.  This	can be
     		helpful when operating on compressed volumes or sparse files.

Oops, looks like ZFS compression is enabled on my machine…

Let’s try this again!

root@build0:~ # du -h -d 0 -A /usr/local/jails/f130/usr/obj/
 12G    /usr/local/jails/f130/usr/obj/

root@illuriasecurity:~ # du -h -d 0 -A /usr/obj/
 12G    /usr/obj/

Ok! This makes more sense 🙂

Let’s also check with ZFS.

root@illuriasecurity:~ # zfs get compression zroot/usr
NAME       PROPERTY     VALUE     SOURCE
zroot/usr  compression  lz4       inherited from zroot

I wonder what’s the build0 server is doing?

root@build0:~ # zfs get compression zroot/usr
cannot open 'zroot/usr': dataset does not exist

Hn o.O ? Oh yeah, I wonder.

root@build0:~ # mount | grep ' / '
/dev/ufs/rootfs on / (ufs, local, journaled soft-updates)

Okay, this makes much more sense now 🙂

That’s all folks!

Techlife Crisis

This is another migration story, like the one that I wrote back in 2020. Unlike the other story, the motivation of this migration is totally different. It’s emotional instead of technical.

Last year a friend of mine got a new job that I referred her to. She passed the interviews and I helped her to get on-boarded as the employer was a friend of mine and I was pretty familiar with their product. The job was remote and she didn’t have a good laptop. Since I have many laptops I ended up giving her my ThinkPad T480s where she ran Ubuntu. As you can tell the employer was a VERY close friend of mine 🙂

All of this meant that I moved back to my MacBook Pro running macOS. I used to like macOS, for me it was always a rock-solid UNIX system with a proper graphical interface.

Unfortunatly these years the UNIX part is not solid anymore and the graphical interface is more iOS-y eye candy than a proper desktop interface.

But I was okay with that, since I spent most of my time in a terminal running vim, ssh, etc. I’d run typical work apps like Mail.app with GPGSuite and a Slack browser client.

But then something snapped in me. I think it was after the car accident. I spent two weeks at home, not able to work. So I started coding on my open-source projects again, doing some patches in FreeBSD, improving code on software that I like and so on.

I realized that I’ve been an Open Source advocate for years, and yet I was in the Apple ecosystem. Not that I don’t like the Apple ecosystem, don’t get me wrong, but as someone who’s been telling the government to use open source, helping them migrate, giving lectures to students about the open source movement and its history, I felt… bad.

I had this MacBook Pro laptop and this iPhone that both control me more than I can control it.

I contacted my friend again, asking if we can swap the laptops and she told me yes. She actually ended up working at our company and now she has a fancy new MacBook Pro while I came back to my lovely ThinkPad T480s running FreeBSD like I wanted in the first place.

As I mentioned, this time it hit me hard, so I decided to escape non-OSS things completely and now I’m running a Pixel 2 with Lineage OS.

There’s a whole story on how I got that Pixel 2 at this day and age and that story is coming soon. And the funniest thing is, as soon as I completed my transaction/migration to Open Source, I got the news that Apple Pay will finally work in Armenia.

Open Source changed my life when I was a kid in Syria, I learned more about computers because of Open Source and while I got distracted with the cute and nice macOS for a while, it’s time to come back home.

Here’s a screenshot

That’s all folks!

Wrong Indicators

Bryan Cantrill has this amazing talk about debugging where he tells the story of Three Mile Island.

After watching that talk all I thought was “well, let’s hope this doesn’t happen in my life”, and by “my life”, I meant my personal or work server, not my AFK life!

55 days ago my girlfriend and I moved to a new apartment downtown the capital. I like everything about this house, specially that many things are electric, including the stove.

Like a sane person, when I see a stove with multiple levels (1, 2, 3) I assume that the lowest number is the lowest and highest number is the highest.

Now you’d think and say “Antranig, didn’t you notice that your cooking was talking 2 hours, so there must be something wrong?”

Oh no, my friend, very much no. As you can see we have two stove tops, a small one and a big one. Now, the small one is working very fine. At the highest level it heats more than at lowest level.

But the big one, the big stove top, not so much.

We thought that there’s a problem with that top and used it only during slow emergencies.

One day I come home from work and Lilith is laughing. I asked “what happened?” and she replied “you’re not gonna believe this!”

Well she was right, it’s been couple of days now and I still can’t believe this. I mean if both of the stove tops were in reverse order, I would understand that someone was very Unix-y and they wanted to design it similar to nice.

But when each of those knobs are the exact opposite of each other, it makes you think, “why me?”

Why me indeed.

That’s all folks!