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cowboy beepboop
Feb 24, 2001

Tankakern posted:

btrfs is fine and of course you should turn off CoW when using it with a db or large vms

maybe fsync should be fixed instead

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sb hermit
Dec 13, 2016





Mr. Crow posted:

In a non-trolly fashion I don't understand how with the backing of Facebook and RHEL the RAID5/6 issues are still a thing. Is it just fundamentally broken?

it's in fedora, but that is no guarantee that it's in rhel. I think it'll get testing resources but probably not a lot of engineering resources unless someone pays them to do something

facebook talked about what btrfs gets for them: https://engineering.fb.com/2018/10/30/open-source/linux/
Specifically, it's io resource allocation and utilization, which makes a lot of sense, since fair performance utilization can help synchronized tasks become more predictable. I don't think raid 5/6 is necessarily a priority for them, so facebook doesn't put engineering resources towards that use case. Likely because raid 10 is good enough, or they have hardware raid and standalone fibrechannel disk arrays to handle the redundancy.

spankmeister
Jun 15, 2008






RAID 5/6 loving sucks anyway. I don't think anyone really uses it anymore because with disk sizes being what they are today, it takes such a long time to rebuild an array that the chance of a second disk failing while the array is still rebuilding is pretty big.

Antigravitas
Dec 8, 2019

Die Rettung fuer die Landwirte:
Single parity is pretty much obsolete, yes. However, we have half a petabyte of storage in double parity raid, typically 12 disks wide. It can't really be beat if you just need lots of storage. Databases run on the good ol' striped mirrors configuration, though a few also run on double parity raid with a log device. It's fine. Rebuild times are at about 24h during full load, which is pretty close to the average write speed of spinning rust anyway.

Of course we don't turn off checksums or COW for our DBs or VMs, because having those guarantees are why we use ZFS for our data in the first place…

Tankakern
Jul 25, 2007

lol at using zfs for other things than a nas

KozmoNaut
Apr 23, 2008

Happiness is a warm
Turbo Plasma Rifle


It's amazing how much time and energy the ZFS zealots spend on anti-btrfs diatribes.

Meanwhile btrfs users are just truckin' along, perfectly content that ZFS also exists and is also a valid choice of filesystem.

Cybernetic Vermin
Apr 18, 2005

oh yeah, if there is something i've thought about btrfs users it is "this sure is a person not at all invested in how their choice of filesystem is perceived in relation to the other options".

of course the btrfs users are so uninvested that they wouldn't just post to tell you about it, but you can kind of feel it in their presence; there they are, the enlightened people making good technology choices, while not at all talking about it.

KozmoNaut
Apr 23, 2008

Happiness is a warm
Turbo Plasma Rifle


Do you need a donut to sit on?

pseudorandom name
May 6, 2007

the best people are of course the XFS on LVM users who don’t bother you at all

psiox
Oct 15, 2001

Babylon 5 Street Team
is there a compelling reason to use xfs over ext4 these days?

either on lvm for my upcoming storage rigg sounds Okay

Broken Machine
Oct 22, 2010

psiox posted:

is there a compelling reason to use xfs over ext4 these days?

either on lvm for my upcoming storage rigg sounds Okay

i like xfs on linux because nasa uses it, and it reliably works on modest hardware as well. it's needs suiting for me if i'm using linux. i don't know what features ext4 has vs xfs, but you can grow an xfs filesystem and such, it's full featured and robust. i switched to xfs on the rare occasions i use linux, mostly because i had an ext4 filesystem that destroyed itself shortly after install (but well after i'd spent the time to set things up). reinstalled w/ xfs and that pc has worked fine since

The_Franz
Aug 8, 2003

psiox posted:

is there a compelling reason to use xfs over ext4 these days?

either on lvm for my upcoming storage rigg sounds Okay

the main advantage is that it's been heavily optimized for multi-threaded, parallel io workloads, particularly when using an nvme drive. it's also very mature and robust

Poopernickel
Oct 28, 2005

electricity bad
Fun Shoe
ext4 is like internet porn

reliable, most people use it, nobody talks about it

like seriously this has been solved for a long rear end time. Ext4 just works, and I don't ever have to think about whether my filesystem is going to implode and eat ~*mY DaTa*~. It's in every Linux kernel you can find, and even in poo poo like u-boot.

It's the filesystem to use if you don't want to give a poo poo about your filesystem, which is the correct point of view.

FlapYoJacks
Feb 12, 2009

Broken Machine posted:

i like xfs on linux because nasa uses it, and it reliably works on modest hardware as well. it's needs suiting for me if i'm using linux. i don't know what features ext4 has vs xfs, but you can grow an xfs filesystem and such, it's full featured and robust. i switched to xfs on the rare occasions i use linux, mostly because i had an ext4 filesystem that destroyed itself shortly after install (but well after i'd spent the time to set things up). reinstalled w/ xfs and that pc has worked fine since

can XFS shrink yet? I haven’t used it in over a decade.

Kazinsal
Dec 13, 2011

DoomTrainPhD posted:

can XFS shrink yet? I haven’t used it in over a decade.

quick googling suggests that no, as of 2019 this was still not possible

imo just use ext4 unless you have some bizarre niche reason to use something more complex in which case you should leave that kind of highly-available filesystem work to an actual storage appliance

Cybernetic Vermin
Apr 18, 2005

Poopernickel posted:

ext4 is like internet porn

reliable, most people use it, nobody talks about it

like seriously this has been solved for a long rear end time. Ext4 just works, and I don't ever have to think about whether my filesystem is going to implode and eat ~*mY DaTa*~. It's in every Linux kernel you can find, and even in poo poo like u-boot.

It's the filesystem to use if you don't want to give a poo poo about your filesystem, which is the correct point of view.

i agree, and to the point where i indeed do just use ext4 and don't think about it, but i do still hope to see data checksumming/scrubbing roll around in ext4 and xfs, as those are nice not-have-to-worry features. afaik most of the infrastructure is in there since a couple of years back (and was used to build the metadata scrubbing they both do have these days), but still some work to be done.

Antigravitas
Dec 8, 2019

Die Rettung fuer die Landwirte:
I have severe storage admin brain and not having checksumming makes me uneasy. I get an email every time such an error occurs and it makes me extremely paranoid because most of the time dmesg and smart are empty. The disk / controller just returned garbage one day and by the time anyone would notice it would be in our backups as well.

I really hope bcachefs continues advancing. It seems to be on a pretty solid basis.

Data I don't care about still resides on ext4, because ext4 is the default. XFS is good, but it's also the only file system besides btrfs that has ever completely destroyed itself. One day after a routine reboot $HOME for 40 workstations wouldn't mount, and that was not a fun day.

zero knowledge
Apr 27, 2008

Kazinsal posted:

quick googling suggests that no, as of 2019 this was still not possible

imo just use ext4 unless you have some bizarre niche reason to use something more complex in which case you should leave that kind of highly-available filesystem work to an actual storage appliance

"bizzare niche reason" such as resizing filesystems, which is how the OS updaters on "bizarre niche" systems like iOS and many (most?) Android devices on the planet deal with increases in OS image size?

I'm glad you've never had to deal with storage problems, which suggests you're working at a reasonable level of abstraction, but that probably has more to do with there being a team somewhere, whether at your employer or at the vendor whose OS you use, who spend a lot of time to this day working on this "solved problem".

Cybernetic Vermin
Apr 18, 2005

Spazmo posted:

"bizzare niche reason" such as resizing filesystems, which is how the OS updaters on "bizarre niche" systems like iOS and many (most?) Android devices on the planet deal with increases in OS image size?

I'm glad you've never had to deal with storage problems, which suggests you're working at a reasonable level of abstraction, but that probably has more to do with there being a team somewhere, whether at your employer or at the vendor whose OS you use, who spend a lot of time to this day working on this "solved problem".

what i learn from this post is that using linux without making complex technical choices yourself, or having a tech support team dedicated to you, is impossible or at least inadvisable

spankmeister
Jun 15, 2008






idk you can just install ubuntu or fedora or something like that and just not worry about the filesystem it uses?

The_Franz
Aug 8, 2003

spankmeister posted:

idk you can just install ubuntu or fedora or something like that and just not worry about the filesystem it uses?

of course you can, but...

*taps thread title*

Poopernickel
Oct 28, 2005

electricity bad
Fun Shoe

Spazmo posted:

"bizzare niche reason" such as resizing filesystems, which is how the OS updaters on "bizarre niche" systems like iOS and many (most?) Android devices on the planet deal with increases in OS image size?

I'm glad you've never had to deal with storage problems, which suggests you're working at a reasonable level of abstraction, but that probably has more to do with there being a team somewhere, whether at your employer or at the vendor whose OS you use, who spend a lot of time to this day working on this "solved problem".

you -do- know that ext4 is resizable, right? Resize2fs works great. I've shipped it in lots of firmware and it's never been an issue.

KozmoNaut
Apr 23, 2008

Happiness is a warm
Turbo Plasma Rifle


Yeah, it's Xfs that can't be shrunk, ext4 is no problem.

It's super useful to shrink disk images so you can use them on a smaller disk as long as there is enough free space.

Antigravitas
Dec 8, 2019

Die Rettung fuer die Landwirte:
Imagine having to unmount to shrink a file system :smugdog:

Lysidas
Jul 26, 2002

John Diefenbaker is a madman who thinks he's John Diefenbaker.
Pillbug
xfs is better than ext4 because it doesnt make/want a lost+found directory off the root of the filesystem

Best Bi Geek Squid
Mar 25, 2016
just lmao imagining having strong feelings about filesystems

pseudorandom name
May 6, 2007

Lysidas posted:

xfs is better than ext4 because it doesnt make/want a lost+found directory off the root of the filesystem

xfs_repair will create one for you

sb hermit
Dec 13, 2016





down the filesystem hole lies madness, and sometimes murder

psiox
Oct 15, 2001

Babylon 5 Street Team
are there any good choices for filesystems with checksumming other than zfs? dangit i feel like that's a must-have for a big nas but i could always go back to running integrit regularly (or whatever the preferred checksum db creation/checking software is these days)

KozmoNaut
Apr 23, 2008

Happiness is a warm
Turbo Plasma Rifle


Yeah, btrfs.

Bcachefs is promising, but not ready yet.

Those are pretty much your realistic options.

Antigravitas
Dec 8, 2019

Die Rettung fuer die Landwirte:
Well, aside from bcachefs, there is ceph…

…but that way lies eldritch horror. With checksums tho

sb hermit
Dec 13, 2016





psiox posted:

are there any good choices for filesystems with checksumming other than zfs? dangit i feel like that's a must-have for a big nas but i could always go back to running integrit regularly (or whatever the preferred checksum db creation/checking software is these days)

btrfs

Captain Foo
May 11, 2004

we vibin'
we slidin'
we breathin'
we dyin'

sb hermit posted:

down the filesystem hole lies madness, and sometimes murder

Progressive JPEG
Feb 19, 2003

i just have ext4 and its fine. partition is encrypted on the desktop anyway so filesystem selection probably doesn't change anything in terms of performance

might try xfs if/when i reformat and drop the encryption since it isn't really needed anymore and the desktop does indeed have an nvme drive

everything else is sata (or usb3 for rpis lol) so they'll probably stick with ext4

Sapozhnik
Jan 2, 2005

Nap Ghost
encrypt all ur filesystems if for no other reason than you can instantly and securely wipe them if you need to throw them out (or just not wipe them and not care)

Lysidas posted:

xfs is better than ext4 because it doesnt make/want a lost+found directory off the root of the filesystem

FlapYoJacks
Feb 12, 2009
Reiser4 does checksums. :v:

sb hermit
Dec 13, 2016





modern processors have built in acceleration for aes encryption/decryption so might as well just turn on encryption unless you can't be bothered to enter the code to decrypt your drives.

Also, for enterprises, you can setup network bound disk encryption which makes decryption entirely automated.

pseudorandom name
May 6, 2007

psiox posted:

are there any good choices for filesystems with checksumming other than zfs? dangit i feel like that's a must-have for a big nas but i could always go back to running integrit regularly (or whatever the preferred checksum db creation/checking software is these days)

turn on integrity for the RAID LV containing the filesystem

Truga
May 4, 2014
Lipstick Apathy

Antigravitas posted:

Well, aside from bcachefs, there is ceph…

…but that way lies eldritch horror. With checksums tho

what are the issues with ceph?

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Antigravitas
Dec 8, 2019

Die Rettung fuer die Landwirte:
It's a distributed network file system not known for its simplicity. It's a Bagger 288 when all you need is a proper shovel.

The shovel is ZFS in this analogy, btw.

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