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Nullfs: A virtual black hole file system that behaves like /dev/null
- drclau 5y agoFYI, the name conflicts with FreeBSD’s nullfs [0][1], which does something entirely different. [0]: https://www.freebsd.org/cgi/man.cgi?query=nullfs&sektion=5 https://www.freebsd.org/cgi/man.cgi?query=nullfs&sektion=5 [1]: https://www.freebsd.org/cgi/man.cgi?query=mount_nullfs&sektion=8&format=html https://www.freebsd.org/cgi/man.cgi?query=mount_nullfs&sekti...
- VWWHFSfQ 5y agoThis looks like it's a Linux kernel module. Not FreeBSD
- NieDzejkob 5y agoI can't see how you'd even begin to think that.
- codetrotter 5y agoI think what they mean is that https://github.com/abbbi/nullfsvfs https://github.com/abbbi/nullfsvfs is a Linux kernel module. Still I don’t know why they bring that up as it’s still true as the parent to that comment said, that it collided with the name in FreeBSD. But I don’t think name collisions matter anyway either, except in the case of trademarks.
- krylon 5y agoI was wondering at first what this might be used for, but for testing it makes perfect sense.
- bartvk 5y agoI remember reading the BOFH series (Bastard Operator From Hell), where a horrible sysadmin would back up to null, because it was so efficient.
- frost_knight 5y agoEverything sent to /dev/null can eventually be retrieved from /dev/random, given sufficient time.
- taftster 5y agoOnly if you believe that /dev/random is truly random.
- usmannk 5y agoEven a truly random die is not guaranteed to ever roll a 6.
- amscanne 5y ago“ever” implies the limit of time. Since lim_{t->Inf} p(at least one 6 is rolled) = 1, I think you could say it’s guaranteed.
- ithkuil 5y agoif it has once, it will again https://en.wikipedia.org/wiki/Poincar%C3%A9_recurrence_theorem https://en.wikipedia.org/wiki/Poincar%C3%A9_recurrence_theor...
- contravariant 5y agoThough it does eventually roll a 6 almost always. Which is math speak for 100% of the time.
- IncRnd 5y agoYet, it probably will.
- cogman10 5y agoWhy would you do this instead of tmpfs?
- abbbi 5y agobcs tmpfs stores the data in your memory. The module was simply created from the need to send large data into the void, where the application writing the data also depends on a directory structure to be existant, for performance testing specially. (if you want to eliminate any underlying fs layer as performance bottleneck, it can sometimes be helpful :))
- Buttons840 5y agoSend data into the void? Consider https://devnull-as-a-service.com/ https://devnull-as-a-service.com/
- n4bz0r 5y ago> Now with Discard protocol support! See Code for details. I certainly didn't read that right the first time.
- Crontab 5y agoUnless I am misreading it, you can configure this to allow some real files to be created, so it isn't all or nothing. But of course those real files will use memory.
- WFHRenaissance 5y agoReminds me of MySQL's BLACKHOLE storage engine: https://dev.mysql.com/doc/refman/8.0/en/blackhole-storage-engine.html https://dev.mysql.com/doc/refman/8.0/en/blackhole-storage-en...
- deleted 5y ago[deleted]
- distantsounds 5y agoWill my mongodb instance be even faster piping to this instead of /dev/null?
- firefwing24 5y agoDoes this also support sharding?
- Tempest1981 5y agoYes, maximum horizontal database scaling can be achieved using shards backed by nullfs.
- aledalgrande 5y agoAlso shard keys are automatically managed.
- gscho 5y agoWith strong consistency as well.
- deleted 5y ago[deleted]
- rberg 5y agoit will be w e b s c a l e
- krackers 5y agoFor those who didn't get the reference: https://www.youtube.com/watch?v=b2F-DItXtZs https://www.youtube.com/watch?v=b2F-DItXtZs
- mike_d 5y agoNice to see open source versions of core Azure services.
- therein 5y agoAt my startup we have been relying heavily on the cloud version of this open-source service for our customer data. [0] I'll try to convince my manager to see if we could deploy this on our K8s cluster. [0] https://devnull-as-a-service.com/ https://devnull-as-a-service.com/
- bofh23 5y agoHehe. I’m reminded of the S4 storage service: S4 - Super Simple Storage Service http://www.supersimplestorageservice.com/ http://www.supersimplestorageservice.com/ « S4's state-of-the-art write-only interface removes the headaches commonly associated with reading data. »
- xbar 5y agoI've long dreamed of the write-only filesystem.
- bofh23 5y agoYour prayers have been answered! S4 - Super Simple Storage Service http://www.supersimplestorageservice.com/ http://www.supersimplestorageservice.com/ « a new innovation in cloud storage. Our advanced write-only storage provides the highest security, lowest cost, and simplest management available. »
- torcete 5y agoThis looks like just a reimplementation of the write-only memory, that was first developed in 1975 by Professor Homberg T. Farnsfarfle
- kblev 5y agoNice to see an open source version of WD My Book Live
- sabalaba 5y agoAmazing, software truly is eating the world.
- bobwaycott 5y agoI got a helluva chuckle out of this. Thanks.
- ComodoHacker 5y agoStill needs improvement to be a real time bomb.
- alpb 5y agoAt first I thought "oh yet another college homework with FUSE API". But this is actually a non-trivial implementation since it's a kernel module, and it doesn't just discard the syscalls (and pretend it worked). It preserves file attrs, sizes and directory entries. > It can handle regular file operations like mkdir/rmdir/ln but writing to files does not store any data. The file size is however saved, so reading from the files behaves like re ading from /dev/zero with a fixed size. > Writing and reading is basically an NOOP, so it can be used for performance testing with applications that require directory structures. Implemented as kernel module, instead of using FUSE, there is absolutely no overhead for copying application data from user to kernel space while performing write or read operations.
- rwmj 5y agoFWIW a null block device: https://libguestfs.org/nbdkit-null-plugin.1.html https://libguestfs.org/nbdkit-null-plugin.1.html + https://libguestfs.org/nbdkit-loop.1.html https://libguestfs.org/nbdkit-loop.1.html It's very useful for testing, in our test suites it's probably the most or second most used plugin.
- davecheney 5y agoPeople who do not understand mongodb will continue to reinvent it.