zfs
squashfs-tools-ng
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zfs | squashfs-tools-ng | |
---|---|---|
719 | 7 | |
10,114 | 187 | |
1.2% | - | |
9.6 | 8.4 | |
6 days ago | about 1 month ago | |
C | C | |
GNU General Public License v3.0 or later | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
zfs
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Radxa's SATA HAT makes compact Pi 5 NAS
> The only non-junk PCIe3 option that's even advertised here recently is the overpriced WD Red SN700.
Those WD drives seem to have some real issues, at least with ZFS and btrfs. :(
https://github.com/openzfs/zfs/discussions/14793
- OpenZFS: Fix corruption caused by MMAP flushing problems
- ZFS: Some copied files are still corrupted (chunks replaced by zeros)
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DiskClick: Ever wanted to hear Old Hard drive sounds
IMO the "next fs" is just zfs. They somewhat recently merged RAIDZ expansion feature https://github.com/openzfs/zfs/pull/12225 and make regular improvements. If no file system has what you need today, zfs will probably be the first one to have it "tomorrow," imo.
- OpenZFS bug reports for native encryption
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A data corruption bug in OpenZFS?
https://github.com/openzfs/zfs/issues/15526#issuecomment-181...
> zpool get all tank | grep bclone
> kc3000 bcloneused 442M
> kc3000 bclonesaved 1.42G
> kc3000 bcloneratio 4.30x
> My understanding is this: If the result is 0 for both bcloneused and bclonesaved then it's safe to say that you don't have silent corruption.
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Ask HN: What's your "it's not stupid if it works" story?
A couple years ago, I had an idea for convincing a filesystem to go faster using 2 compression steps instead of one. I couldn't see why it wouldn't work, and I also couldn't convince myself it should.
It seems to have worked out. [1]
[1] - https://github.com/openzfs/zfs/commit/f375b23c026aec00cc9527...
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ZFS Profiling on Arch Linux
https://github.com/openzfs/zfs/issues/7631
This is a long-standing issue with zvols which affects overall system stability, and has no real solution as of yet.
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Using ZFS on single disks, combining them with mergerfs, and paritizing them with Snapraid
TIL. Thank you! https://github.com/openzfs/zfs/pull/15022
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Why does primarycache=metadata reduce my un-cached read speeds?
Difference may be significant, yes https://github.com/openzfs/zfs/pull/14243
squashfs-tools-ng
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C Strings and my slow descent to madness
... except that that is also subtly broken.
It works if you write multiple UTF-8 code-units in one go, but breaks if you send them in several writes, or if you use the ANSI API (with the A suffix). Guess what the Windows implementation of stdio (printf and friends) does.
I already had some fun with this: https://github.com/AgentD/squashfs-tools-ng/issues/96#issuec...
And we didn't even discuss command line argument passing yet :-)
I tried to test it with the only other two languages I know besides English: German and Mandarin. Specifically also, because the later requires multi-byte characters to work. Getting this to work at all in a Windows terminal on an existing, German Windows 7 installation was an adventure on it's own.
Turns out, trying to write language agnostic command line applications on Windows is a PITA.
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Getting the maximum of your C compiler, for security
IIRC fanalyzer is a fairly recent addition to gcc. Has it become reasonable usable yet?
I recall getting a bit excited when I first read about it, but the results I got where rather bizarre (e.g. every single function that allocated memory and returned a pointer to it was labeled as leaking memory).
It did the fun exercise myself once to riffle through the gcc manpage, cobble together warning flags and massage them into autoconf[1][2].
There is a very handy m4 script in the util-linux source for testing supported warning flags[3].
[1] https://git.infradead.org/mtd-utils.git/blob/HEAD:/configure...
[2] https://github.com/AgentD/squashfs-tools-ng/blob/master/conf...
[3] https://github.com/karelzak/util-linux/blob/master/m4/compil...
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Squashfs turning 20, Squashfs tools 4.5 released
> Honestly I think you could be a little more respectful of the project that inspired yours.
I do. I had a lot of great "Huh? That's clever!" moments while reverse engineering the format and formed a mental image of a clearly brilliant programmer who managed to squeeze the last bits out of some data structures using really clever tricks that I myself probably wouldn't have come up with. During that time I gained a lot of respect for the project and the author.
Also, please don't forget: the whole project is the filesystem, the tools are just a part of that. I care about this project, which is why I decided to start this effort in the first place. Which I explicitly did not advertise as a replacement, but an augmentation (see [2]).
> I'd be angry too ... Definitely understandable.
Yes, I agree! And I can understand why in the heat of the moment you might write something angry and threatening. But certainly not if you've had a few weeks time to calm down and think things over.
> And you plagiarized part of his readme.
https://github.com/plougher/squashfs-tools/blob/master/RELEA...
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...
https://github.com/AgentD/squashfs-tools-ng/blob/master/READ...
Oh yes? Which part?
> ... calling it spaghetti code (which isn't immediately verifiable)
Here you go, have fun: https://github.com/plougher/squashfs-tools/blob/master/squas...
However, I cannot blame anyone here, I totally get how those things happen and have witnessed it myself in action:
You write a simple tool supporting a larger project. It's written by the seat of your pants without much planning, since it's not big and does one simple job. Then it gets used in production, eventually requirements change, other people pile on patches, but try to keep the diff small, so it's reviewable and it receives maybe a little less care than the actual project it supports. Nobody bothers to overhaul it or write documentation because, hey, it works, and any large changes might risk breaking things.
Even if nobody is to blame for it, the end result is still the same: an undocumented mess that is hard to wrap your head around if you aren't the original author, who is the only one with the bigger picture.
I tried for roughly a week to pull the code (there are some more files than this and some of the inter dependencies are nasty) apart into stacked utility libraries and a pure command line parsing front end, with the hopes to maybe get this upstream once it is done. I gave up and decided that at this point I understood enough about the format to start afresh and not touch what I believed to be an unmaintained mess.
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The Byte Order Fiasco
FWIW there is an on various BSDs that contains "beXXtoh", "leXXtoh", "htobeXX", "htoleXX" where XX is a number of bits (16, 32, 64).
That header is also available on Linux, but glibc (and compatible libraries) put named it instead.
See: man 3 endian (https://linux.die.net/man/3/endian)
Of course it gets a bit hairier if the code is also supposed to run on other systems.
MacOS has OSSwapHostToLittleIntXX, OSSwapLittleToHostIntXX, OSSwapHostToBigIntXX and OSSwapBigToHostIntXX in .
I'm not sure if Windows has something similar, or if it even supports running on big endian machines (if you know, please tell).
My solution for achieving some portability currently entails cobbling together a "compat.h" header that defines macros for the MacOS functions and including the right headers. Something like this:
https://github.com/AgentD/squashfs-tools-ng/blob/master/incl...
This is usually my go-to-solution for working with low level on-disk or on-the-wire binary data structures that demand a specific endianness. In C I use "load/store" style functions that memcpy the data from a buffer into a struct instance and do the endian swapping. The copying is also necessary because the struct in the buffer may not have proper alignment.
In C++ code, all of this can of course be neatly stowed away in a special class with overloaded operators that transparently takes care of everything and "decays" into a single integer and exactly the above code after compilation, but is IMO somewhat cleaner to read and adds much needed type safety.
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Tar is an ill-specified format
I once foolishly thought, I'll write a tar parser because, "how hard can it be" [1].
I simply tried to follow the tar(5) man page[2], and got a reference test set from another website posted previously on HN[3].
Along the way I discovered that NetBSD pax apparently cannot handle the PAX format[3] and my parser inadvertently uncovered that git-archive was doing the checksums wrong, but nobody noticed because other tar parsers were more lax about it[4].
As the article describes (as does the man page), tar is actually a really simple format, but there are just so many variants to choose from.
Turns out, if you strive for maximum compatibility, it's easiest to stick to what GNU tar does. If you think about it, IMO in many ways the GNU project ended up doing "embrace, extend, extinguish" with Unix.
[1] https://github.com/AgentD/squashfs-tools-ng/tree/master/lib/...
[2] https://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5
[3] https://mgorny.pl/articles/portability-of-tar-features.html
[4] https://www.spinics.net/lists/git/msg363049.html
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LZ4, an Extremely Fast Compression Algorithm
A while ago I did some simplistic SquashFS pack/unpack benchmarks[1][2]. I was primarily interested in looking at the behavior of my thread-pool based packer, but as a side effect I got a comparison of compressor speed & ratios over the various available compressors for my Debian test image.
I must say that LZ4 definitely stands out for both compression and uncompression speed, while still being able to cut the data size in half, making it probably quite suitable for life filesystems and network protocols. Particularly interesting was also comparing Zstd and LZ4[3], the former being substantially slower, but at the same time achieving a compression ratio somewhere between zlib and xz, while beating both in time (in my benchmark at least).
[1] https://github.com/AgentD/squashfs-tools-ng/blob/master/doc/...
[2] https://github.com/AgentD/squashfs-tools-ng/blob/master/doc/...
[3] https://github.com/AgentD/squashfs-tools-ng/blob/master/doc/...
What are some alternatives?
zstd - Zstandard - Fast real-time compression algorithm
squashfs-tools - tools to create and extract Squashfs filesystems
7-Zip-zstd - 7-Zip with support for Brotli, Fast-LZMA2, Lizard, LZ4, LZ5 and Zstandard
sanoid - These are policy-driven snapshot management and replication tools which use OpenZFS for underlying next-gen storage. (Btrfs support plans are shelved unless and until btrfs becomes reliable.)
dracut - dracut the event driven initramfs infrastructure
RocksDB - A library that provides an embeddable, persistent key-value store for fast storage.
genext2fs - genext2fs - ext2 filesystem generator for embedded systems
snapper - Manage filesystem snapshots and allow undo of system modifications
zfsbootmenu - ZFS Bootloader for root-on-ZFS systems with support for snapshots and native full disk encryption
LZ4 - Extremely Fast Compression algorithm