Why isn't BTRFS the default FS in home-oriented Linux distributions?

Question

I have been looking how BTRFS has been progressing. It supports CoW, snapshots, data deduplication, compression, data integrity, (...), a list of features that are unavailable in EXT4 (the current default FS in most home-oriented Linux distributions).For granted, EXT4 keeps being faster than BTRFS in most synthetic benchmarks, which makes it a better choice for servers, but this difference in speed isn't noticeable in domestic workloads; domestic users would greatly benefit from the features offered by BTRFS. For example, Linux Mint has Timeshift, a backup solution that uses BTRFS volumes to make system snapshots.This leads me to my question: Why haven't we switched to BTRFS as the default FS for home-oriented distributions? What features / reasons are holding us to keep using EXT4 as the default FS?

ranger207 · Accepted Answer

The rule of thumb is that a filesystem needs about a decade or so[0] to iron out the bugs and become reliable enough for regular use by regular users. Btrfs is 14 years old which means it's old enough to start getting adopted, but changing the default filesystem in a distro is not a particularly quick process, since most people simply don't care about most of the advanced features. Plus since data loss is such a feared problem, any anecdotes about it will cause a massive hit to the filesystem's reputation, regardless of the anecdote's validity. Right now Fedora and OpenSUSE use btrfs by default, likely because they're upstreams of enterprise distros where users will use those advanced features, so Red Hat and SUSE want to make sure it's as solid as possible before potentially rolling it out to paying customers.
Personally, I'm a happy user of btrfs installed by default by Fedora and haven't had any problems with it, but I'm also not using any of the advanced features.
[0] Source: casual conversation and poorly remembered anecdotes

nvarsj · Answer

It already is. OpenSUSE and Fedora both use brtfs by default now. It&rsquo;s by far the most sensible fs for modern desktop usage and a killer feature of Linux.

jiggawatts · Answer

Just a friendly warning: BTRFS isn't anywhere near as robust as ZFS, which in turn has had a long history of problems.
There were some threads on HN related to BTRFS which made me look into its suitability as a RAID5 or RAID6 file system, and what I saw made me back-pedal very fast.
Its support for RAID1 or RAID10 (mirroring or stripe-mirror) is okay, but it has glaring issues in all other modes that have gone unresolved for many years. There are some fundamental design issues that might mean that these problems will never get solved, with data loss or data corruption being the inevitable consequence.
Storage is like multi-threading: you've either mathematically proved the correctness of your algorithm, or it is Wrong with a capital W. Storage is not like a web app where an occasional HTTP/500 is no big deal and recoverable. You stuff up something even a tiny bit, and the consequence is shredded or lost data and a very bad day for someone somewhere.
I'm just not seeing the right attitude from the team working on BTRFS. They've been very lax about data integrity issues, recovery from expected failures, etc...
My advice is: stay away.

rhn_mk1 · Answer

In my experience, btrfs has one significant disadvantage over ext4. It's the behaviour once the partition is full. It's relatively easy to get stuck in a state where you can't delete anything because of the fullness. In some cases it's only recoverable by extending the partition, deleting, and then removing the extension.

guardiangod · Answer

I am using both. I've lost data on both, and near misses that required hair-raising metadata rebuild.BTRFS documentation still greatly trail behind ZFS, imo. It's RAID1 implementation is subpar in terms of monitoring.

selfhoster11 · Answer

I lost data with Btrfs, whereas ext4 has been rock solid for many years. No thanks.

jacknews · Answer

Nope.Sorry, it's the only FS I've lost data with. It seems to have a problem when disks start getting hardware errors and some blocks become unreadable. I mean of course any FS suffers in this situation, but most don't lose the entire volume as easily as btrfs seems to.

ianai · Answer

My question is why in 2023 isn&rsquo;t there some better efforts to at least bring third party support for the various FSes to the various OSes?Or is it a side effect of streaming everything? Ie who cares. Ie file systems are solved tech and nothing really new until permanent storage is as fast as RAM in all aspects, replaces it, and we get some new computing paradigm.

znpy · Answer

1 - increased complexity, makes troubleshooting harder
2 - higher risk of losing data
3 - harder to explain and understand vs ext4.
4 - has more special needs. in some cases you need way more free storage for rebalancing stuff around... you don't need that for ex4.
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now ext4 is surely worse than btrfs... but for the average home user btrfs is more of a problem than a solution, probably.

jacooper · Answer

I never used any of its advanced feature, and it makes managing volumes unnecessarily difficult

whitefang · Answer

I would love to learn why ZFS and BTRFS are competing to a common-ish goal?

stuaxo · Answer

My raspberry pi with a slightly power supply got the filesystem into a state I couldn't recover it from when I tested it last.I am using it again but on a NAS with a backup battery.

shashurup · Answer

I've considered trying it several times, and each time failed to find any practical use case for my scenarios.

nubinetwork · Answer

Have they fixed raid 5 yet? Last time I checked, they said "we don't care" and declared it stable.

graypegg · Answer

How often are people reevaluating their file system choice? As excited as Linux users tend to be about the little things, the file system is so close to being unnoticeable day-to-day that it&rsquo;s not worth the hassle when the current one works perfectly fine.

transfire · Answer

I&rsquo;ve heard it lacks maturity and of a few cases of data corruption. Those cases are no doubt outdated now, but I haven&rsquo;t heard any news to sway me that BTRFS is ready for prime time.Ditto for ZFS btw.

Why isn't BTRFS the default FS in home-oriented Linux distributions?

It already is. OpenSUSE and Fedora both use brtfs by default now. It’s by far the most sensible fs for modern desktop usage and a killer feature of Linux.

I am using both. I've lost data on both, and near misses that required hair-raising metadata rebuild.
BTRFS documentation still greatly trail behind ZFS, imo. It's RAID1 implementation is subpar in terms of monitoring.

I lost data with Btrfs, whereas ext4 has been rock solid for many years. No thanks.

Nope.
Sorry, it's the only FS I've lost data with. It seems to have a problem when disks start getting hardware errors and some blocks become unreadable. I mean of course any FS suffers in this situation, but most don't lose the entire volume as easily as btrfs seems to.

I never used any of its advanced feature, and it makes managing volumes unnecessarily difficult

I would love to learn why ZFS and BTRFS are competing to a common-ish goal?

My raspberry pi with a slightly power supply got the filesystem into a state I couldn't recover it from when I tested it last.
I am using it again but on a NAS with a backup battery.

I've considered trying it several times, and each time failed to find any practical use case for my scenarios.

Have they fixed raid 5 yet? Last time I checked, they said "we don't care" and declared it stable.

How often are people reevaluating their file system choice? As excited as Linux users tend to be about the little things, the file system is so close to being unnoticeable day-to-day that it’s not worth the hassle when the current one works perfectly fine.

I’ve heard it lacks maturity and of a few cases of data corruption. Those cases are no doubt outdated now, but I haven’t heard any news to sway me that BTRFS is ready for prime time.
Ditto for ZFS btw.