JFS on Linux

techguy378 · 2020-06-13 21:11:19

Just curious, is there any disadvantage to using JFS on Linux? There's very little information about the filesystem after it was ported to Linux and OS/2 was largely discontinued. The only information I was able to find is that in non-RAID configurations JFS is substantially faster than ZFS and every other Linux filesystem in all use cases. Apparently JFS is far more resistant to data loss that ZFS. Is there any particular reason JFS is seldom used on Linux computers, even personal ones?

jasonwryan · 2020-06-13 21:15:19

https://wiki.archlinux.org/index.php/JFS Worth reading the Talk page as well.

Lead dev is an Oracle employee. Just sayin'.

techguy378 · 2020-06-14 02:46:11

I read that article. It claims that JFS suffers massive performance degradation due to fragmentation but that's not true because IBM says that in all operating systems that support JFS that the filesystem does online defragmentation. The only other complaints I've heard are that JFS causes massive data loss, especially in heavy I/O workloads but that doesn't seem to be true either.

https://www.linux.com/news/30-days-jfs/

jasonwryan · 2020-06-14 02:48:53

It's your system, install it and make up your own mind. Personally, I will stick with ext4.

techguy378 · 2020-06-14 03:00:54

Was hoping to get an answer from somebody who has had more experience with JFS before deciding whether or not to make the switch. The Arch Linux forums don't exist for the sole purpose of telling people to simply Google it.

jasonwryan · 2020-06-14 03:11:02

techguy378 wrote:

Was hoping to get an answer from somebody who has had more experience with JFS before deciding whether or not to make the switch. The Arch Linux forums don't exist for the sole purpose of telling people to simply Google it.

Thanks for telling me the purpose of the boards...

seth · 2020-06-14 06:05:22

It claims that JFS suffers massive performance degradation due to fragmentation but that's not true because IBM says

"somebody said X, but that's not true because somebody else said Y"

What you wanted to say is something like "it's not true because the wiki cites a mail from 2006 and here's a link where IBM more recently claims it to exist"

complaints I've heard are that JFS causes massive data loss, especially in heavy I/O workloads but that doesn't seem to be true either

"I've heard complaints about X, but that doesn't seem true"

The wiki eplains why JFS lazy journal is prone to data loss.

You might have figured that it's hard to find, esp. recent, information on JFS (seems to fade out w/ the widespread distribution of ext4) what (along the wikipedia article which is also full of unsourced claims) tells me the FS is rarely used and rarely used stuff tends to be more buggy than code which a gazillion people smash against their weird setups and configs all the time.

I therefore wouldn't test it on a productive system where data integrity or uptime matter.

tpfkanep · 2020-06-14 07:23:10

JFS is substantially faster than ZFS and every other Linux filesystem in all use cases

Was my experience as well in the past. It runs pretty smooth with meager resources. A joy. Have not used it in years as my main fs (I still have some old JFS HDDs), mainly due to the fact that I could not get a swapfile (for hibernation) working on it.

I have given up hope for JFS to gain more popularity...

finoderi · 2020-06-14 08:36:31

I used JFS once on my root partition in Ubuntu. I haven't noticed it being faster than ext3. One day it just died for no particular reason. Although it was a while ago in 2008 or 2009. It doesn't necessarily mean much, just anecdotal evidence for you.

ewaller · 2020-06-14 16:28:29

I had jfs on a spinning hard drive in this laptop. No issues at all. I just retired that drive with 42,000 hours on it (the soft read error rate was bending upwards).
It was indistinguishable from ext4 on my system -- a laptop running i3 and Gnome.
I am back with ext4 on the new SSD.

techguy378 · 2020-06-15 19:14:18

Just reinstalled Arch Linux to a JFS partition. I don't use swapfiles and I'm not sure what the point of them is over a swap partition. JFS is significantly faster that F2FS, ext4 or XFS. Those are the other filesystems I've tried over time. As an example, even when installing over 700 packages during initial install for Gnome and its dependencies, Pacman had them installed in under 10 seconds after the downloads were completed compared to the other three filesystems I mentioned which took 45-60 seconds. Time will tell for reliability and data loss, but so far except for the "man3" directory getting deleted all of the reports claiming JFS ate people's data seem to be fake news. Too bad ZFS can't make that claim.

I'm using a System76 laptop with the following configuration:

Intel Core i7-6700HQ (4C/8T)
16GB RAM
500GB Western Digital SN750 Black NVMe drive
Intel HD 530 graphics

seth · 2020-06-15 20:14:23

seth wrote:

The wiki eplains why JFS lazy journal is prone to data loss.

It's not that data would magically disappear…

wiki wrote:

In JFS; journal writes are indefinitely postponed until there is another trigger such as memory pressure or an unmount operation. This infinite write delay limits reliability, as a crash can result in data loss even for data that was written minutes or hours before

The problem occurs when the FS gets an unclean unmount, similar to https://wiki.archlinux.org/index.php/Ex … journaling

loqs · 2020-06-15 21:32:21

With only a single device, data redundancy using mirror or striping offered by ZFS, BTRFS, lvm2, dm-raid or anything else are not available. ZFS could still provide multiple copies of the data on the same device using the copies property.

twelveeighty · 2020-06-15 22:14:25

techguy378 wrote:

Time will tell [...], but [...] seem to be fake news

It's hard to take anything you're writing here seriously. Just because it didn't fail in the first hour doesn't relegate JFS' lazy journal system to be "fake news". You are trying to get an emotional response from the Arch community but ignore rational statements and advice about JFS. That doesn't mean JFS is shit. It just means that people who know why advice against it under heavy load. And an Arch install is mostly a single process, single thread disk operation, so that hardly counts as "heavy load". Do the install again and force power off the machine in the middle of it. Do that 5 times and see if the file system has had no corruption and data loss 5/5 times.

ewaller · 2020-06-15 22:46:53

I expect civility on this thread. There have already been moderator action against this thread.

https://wiki.archlinux.org/index.php/Co … ther_users
https://wiki.archlinux.org/index.php/Co … o_trolling
https://wiki.archlinux.org/index.php/Co … _not_flame

Next steps will be closing the thread and banning those who engage in ad hominem attacks.

fukawi2 · 2020-06-16 02:32:55

I used to use JFS on my machines 10+ years ago. I never really found any material benefit to it over ext4 or xfs (FWIW, I use XFS and ZFS these days.)

techguy378 wrote:

...JFS is substantially faster than ZFS

Almost certainly true, since JFS is doing a lot less than ZFS.

techguy378 wrote:

Apparently JFS is far more resistant to data loss that ZFS.

I find this hard to believe. Anecdotally, ZFS has a long history of data resiliency. Even without multiple disks, just the check-summing of (meta)data alone would give it better resiliency than any filesystem without check-summing. With copies=2 (or greater) or multiple disk configurations I can't imagine any situation where JFS would provide better resiliency than ZFS. If we're talking about administrative mistakes, then yes you're probably more likely to mess up your ZFS filesystem than your JFS one, but that's not a fault with the filesystem.

Arch Linux

#1 2020-06-13 21:11:19

JFS on Linux

#2 2020-06-13 21:15:19

Re: JFS on Linux

#3 2020-06-14 02:46:11

Re: JFS on Linux

#4 2020-06-14 02:48:53

Re: JFS on Linux

#5 2020-06-14 03:00:54

Re: JFS on Linux

#6 2020-06-14 03:11:02

Re: JFS on Linux

#7 2020-06-14 06:05:22

Re: JFS on Linux

#8 2020-06-14 07:23:10

Re: JFS on Linux

#9 2020-06-14 08:36:31

Re: JFS on Linux

#10 2020-06-14 16:28:29

Re: JFS on Linux

#11 2020-06-15 19:14:18

Re: JFS on Linux

#12 2020-06-15 20:14:23

Re: JFS on Linux

#13 2020-06-15 21:32:21

Re: JFS on Linux

#14 2020-06-15 22:14:25

Re: JFS on Linux

#15 2020-06-15 22:46:53

Re: JFS on Linux

#16 2020-06-16 02:32:55

Re: JFS on Linux

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