The Linux Thread - The Autist's OS of Choice

[analrapist]

If I do that, then how do I undo that?

Delete the caret ("not").

enable journal:

sudo tune2fs -O has_journal /dev/drivename

Also, I fucked that last one up, should be tune2fs, not mke2fs. In other words,

disable journal:

sudo tune2fs -O ^has_journal /dev/drivename

 

[ToroidalBoat]

hey @analrapist (lol @ username)

So if I get this right, it is...

disable: sudo tune2fs -O ^has_journal /dev/[drivename]
enabled: sudo tune2fs -O has_journal /dev/[drivename]

... and not that earlier sudo mke2fs -t ext4 -O ^has_journal /dev/drivename thing?

 

[analrapist]

hey @analrapist (lol @ username)

So if I get this right, it is...

disable: sudo tune2fs -O ^has_journal /dev/[drivename]
enabled: sudo tune2fs -O has_journal /dev/[drivename]

... and not that earlier sudo mke2fs -t ext4 -O ^has_journal /dev/drivename thing?

Yep.

https://man7.org/linux/man-pages/man8/tune2fs.8.html -- I double checked the man page. Apparently you need two -f flags when removing the journal because they don't want people to do it because if you've had an unclean poweroff, you can lose data.

So, then,

disabled: sudo tune2fs -f -f -O ^has_journal /dev/[drivename]

I reckon you'd probably get told this by trying your disabled command without the -f. Been a while since I've done this.

 

[DavidS877]

Let me just state for the record that turning off a filesystem journal is a Reddit tier move. Outside of some super specialized cases needing reduced latency about all it does is increase the chances of lost files in case of a system crash or unexpected power cut.

 

[analrapist]

Outside of some super specialized cases needing reduced latency about all it does is increase the chances of lost files in case of a system crash or unexpected power cut.

I don't disagree that it's disrecommended. Write-limited contexts like flash storage show some improvements as well. That's the core of what ToroidalBoat is getting at. I agree, you usually want a journal, but turning it off does decrease writes, which is what his aim is.

 

[DavidS877]

I don't disagree that it's disrecommended. Write-limited contexts like flash storage show some improvements as well. That's the core of what ToroidalBoat is getting at. I agree, you usually want a journal, but turning it off does decrease writes, which is what his aim is.

Doesn't matter if your SSD lasts 3% longer when your system crashes and ends up with half the files in /lost+found
I mean, maybe on a MicroSD or something.

The correct solution is to monitor the smart data and see where the lifetime really is. My root/home drive on my main fileserver which also runs some databases and other containers is all the way down to 99% lifetime after 70TB written and 6 years.

 

[analrapist]

Doesn't matter if your SSD lasts 3% longer when your system crashes and ends up with half the files in /lost+found
I mean, maybe on a MicroSD or something.

MicroSD on Raspberry Pi and other ARM rigs are the chief place I've used this. I've routinely shut these systems down by just cutting power. The concern about corruption is quite overstated, so long as you're not pulling the power while writing something you care about or during an update or something.

 

[Samuel Fuller]

Exactly why I love how the BSDs, especially Net/OpenBSD do things in regards to cleaning up redundant code. One can only imagine how much time and effort it would take to audit current day Windows like that from the bottom up. Might as well rewrite the entire thing at that point.

That was the conclusion MS came to that led to the failed Longhorn initiative.

 

[ToroidalBoat]

disabled: sudo tune2fs -f -f -O ^has_journal /dev/[drivename]

Are those double -f needed when re-enabling?

 

[Belisarius Cawl]

ALT-PRINTSCREEN-REISUB. In case your console isn't working either.

Those might require altered permissions to work

MicroSD on Raspberry Pi and other ARM rigs are the chief place I've used this. I've routinely shut these systems down by just cutting power. The concern about corruption is quite overstated, so long as you're not pulling the power while writing something you care about or during an update or something.

I absolutely beg to differ. If I ever run a Raspberry Pi again it's going to boot from an external HD.

 

[analrapist]

Are those double -f needed when re-enabling?

According to the manual, no. Double -f is the faggot Red Hat "Are you really sure you want to do this? I expect my users to be niggers." paranoia.

I absolutely beg to differ.

Using ext4 specifically? Mounted with sync? What kind of setup? I'm a DWM/X guy, so I've got a lot fewer niggerlicious GNOME processes to break.

 

[Belisarius Cawl]

Using ext4 specifically? What kind of setup? I'm a DWM/X guy, so I've got a lot fewer niggerlicious GNOME processes to break.

I wasn't looking at mount or /etc/fstab when my Pis shat themselves but presumably "yes" to ext4. But since Alt+SysRq was mentioned earlier (REISUB), one thing that anyone using Linux should also know, especially with disgustingly bloated browser software, is Alt+SysRq+F, which will target the first memory-intensive task it can find and so on. It won't reboot your system like REISUB does. Also be aware that you will likely have to alter administrative privileges for this chord to work. Oh and to answer your question: LXDE and Xfce4.

 

[Betonhaus]

That was the conclusion MS came to that led to the failed Longhorn initiative.

It only failed because there was so much legacy code that they needed compatibility for. They could've done some sort of Windows on Windows system where all legacy applications run inside a protected container with compatibility APIs, and that container could eventually be made optional and removed for more streamlined systems like netbooks or tablets or even phones

 

[ToroidalBoat]

hey @analrapist

I've noticed just browsing files in the file browser can cause that "jbd2" thing to do multi-megabytes of writes, especially if it's in the OS partitions. Is that BS normal?

 

[DavidS877]

Those might require altered permissions to work

I absolutely beg to differ. If I ever run a Raspberry Pi again it's going to boot from an external HD.

I have around 12 Pis running. I lose a MicroSD every couple years. Even the ones that do stuff locally like the weather station don't seem to have problems. Sure, I should move it to an external DB, but whatever.

 

[Belisarius Cawl]

I have around 12 Pis running. I lose a MicroSD every couple years. Even the ones that do stuff locally like the weather station don't seem to have problems. Sure, I should move it to an external DB, but whatever.

It's a pain in the ass to have to start all over, even with scripts to help you. But why go through all of that?

 

[analrapist]

I've noticed just browsing files in the file browser can cause that "jbd2" thing to do multi-megabytes of writes, especially if it's in the OS partitions. Is that BS normal?

"Browsing files in the file browser" usually means that if there's no cached version available, they're going to be read to see what they are, maybe thumbnailed, etcetera. Megabytes of writes could just be thumbnails/filetype-caching. Of course, the reads are going to mean there's also atime write once per day.

Continuing on the ext4-without-journal bit, here's an ARM hardware vendor recommending disabling journaling, and the things they do to make non-journaled ext4 safe/performant:

https://developer.ridgerun.com/wiki/index.php/High_performance_SD_card_tuning_using_the_EXT4_file_system

 

[DavidS877]

Also be aware that you will likely have to alter administrative privileges for this chord to work.

sudo cat /proc/sys/kernel/sysrq
If it's 1 then all are enabled, 0 all are disabled, some other number then some are enabled.

https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html

sudo sysctl kernel.sysrq=1 to enable all

Depending on your system to make a change permanent you can probably add kernel.sysrq=1 to /etc/sysctl.conf or a file in /etc/sysctl.d/

 

[Belisarius Cawl]

sudo cat /proc/sys/kernel/sysrq
If it's 1 then all are enabled, 0 all are disabled, some other number then some are enabled.

https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html

sudo sysctl kernel.sysrq=1 to enable all

Depending on your system to make a change permanent you can probably add kernel.sysrq=1 to /etc/sysctl.conf or a file in /etc/sysctl.d/

All of that is correct and might benefit other Linux users or more specifically Pi users here (though maybe security-oriented users might not want to turn on every feature like I did). Still, my main concern remains running an operating system from a microSD card. It's fishy at a bare minimum.

 

[ToroidalBoat]

The Linux-running computer I'm on is about 5 years old now. The TBW to the SSD is now almost 20 TB.

The main reasons* for such a ridiculous amount of writing...

• not disabling "Safe Browsing" via Firefox (every 20 to 30 minutes a blacklist of bad URLS of over 20 MB is downloaded from Google)
• watching videos in Firefox without using Private Browsing with browser.privatebrowsing.forceMediaMemoryCache set to true
• watching YouTube videos on that main crapsite or on youtube.com/embed/[vid code]
• using GMail or some other sites in normal browsing (not Private Browsing)
• not disabling logging with systemd and rsyslog
• not disabling logging in uBlock

... and all that is despite disabling caching in Firefox.

* (along with whatever the previous user used it for)

With all that, this is what the SMART thing says:

Available Spare:                    100%
Available Spare Threshold:          10%
Percentage Used:                    2%