[HN Gopher] Ask HN: I'd like an OS/FileSystem that Never Deletes...
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Ask HN: I'd like an OS/FileSystem that Never Deletes Anything. Does
it exist?
Forgive me for the ignorance of my question. I'm tired creating
backups, or loosing data. Let's be honest, sometimes it happens.
Does a filesystem that never deletes/overwrites anything exist? I
envision something like an append only filesystem where you all
files in your hard drive are under some OS level 'version control'
and you can rollback to any version you want. Only files in my home
dir would be enough. Obviously once space runs out it would start
overwriting the oldest versions.
Author : choletentent
Score : 3 points
Date : 2022-02-05 22:05 UTC (56 minutes ago)
| whalesalad wrote:
| I imagine something does exist that does this, but I do not know
| what it is called.
|
| I know that overlayfs exists, which could enable this sort of
| thing by capturing each individual change to the filesystem as a
| new layer.
| https://www.kernel.org/doc/html/latest/filesystems/overlayfs...
|
| Btrfs and ZFS can do snapshotting, and I would imagine it could
| be configured to snapshot at certain intervals or after
| individual changes to the filesystem or a section of the
| filesystem, like watched directories.
|
| https://wiki.archlinux.org/title/Btrfs#Snapshots
|
| https://docs.oracle.com/cd/E19253-01/819-5461/gbcya/index.ht...
|
| There's also filesystem-in-userland tech like Fuse which could
| enable something like this.
| https://www.kernel.org/doc/html/latest/filesystems/fuse.html
| Rebelgecko wrote:
| Look up "append only" filesystems. That'll get you most of the
| way there, but you'll have to manually reset things to get rid of
| old files. Or just use a competent backup system.
| choletentent wrote:
| Let's say you are editing a source code file. You save and you
| run. Than you tweak, save and run again. But then you would
| like to go two changes in the past, but you did not make a
| commit. Very recent changes are not captured by backup systems,
| no matter how competent they are.
|
| I'd like to have all my files under git, for every save - and
| frictionless. I know it is a lot to ask.
| LinuxBender wrote:
| The expensive version of what you are describing is a vaulting
| appliance but I won't continue down that path unless you are a
| bank.
|
| The _affordable_ version of what you are describing is a set of
| NAS class servers that use something like DRBD or Ceph for multi-
| node replication and rsnapshot for local snapshots /versioning if
| LVM. If using LVM, then rsnapshot should be configured to save
| its snapshot where the remote clients can not write to it.
|
| Look into setting up Ceph clusters if you plan to build something
| that will need to scale really large on individual volumes across
| multiple nodes. Ceph supports creating snapshots. There are pros
| and cons to solutions such as DRBD, LVM and Ceph. That would be a
| topic in and of itself. Others here are mentioning ZFS and that
| is also a popular solution but I have never used it and can't
| comment on it.
|
| In summary if I was asked to build something that would grow to
| unknown size, require snapshots to roll-back files to a specific
| date and be fault tolerant I would go with Ceph. As a bonus
| feature there are libraries and tools to present Ceph volumes as
| S3-like buckets. There are ansible playbooks for setting up Ceph
| clusters. Ceph has some really good security features as well.
| Someone wrote:
| > Does a filesystem that never deletes/overwrites anything exist?
|
| > Obviously once space runs out it would start overwriting the
| oldest versions.
|
| You can't have both.
|
| Also, your system wouldn't prevent data loss on hardware
| failures.
|
| What you describe is/may be a WORM device
| (https://en.wikipedia.org/wiki/Write_once_read_many)
| Minor49er wrote:
| I hope this hypothetical OS never needs to use a swap file.
|
| More seriously, in a time of unobtrusive automated backups and
| dirt cheap storage space, why is this such an issue where you
| want to have this kind of system?
| hulitu wrote:
| Domain OS had versioning filesystem. You could always load an
| older version of your file in the editor.
| Minor49er wrote:
| Something similar can be achieved today with a combination of
| autosaves or version saves at the application level as well
| as time machine backups at the OS level
| some_chap wrote:
| Digital's VMS/OpenVMS had something that was a fair way towards
| this, in that a file was created with a version number
| (myfile.txt;1) and when modified, a 2nd file (myfile.txt;2) was
| created, and so on...
|
| In practice we used to work on things then purge when happy with
| the final changes, as we didn't have that much 'spare' disk, but
| it was a nice feature.
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(page generated 2022-02-05 23:02 UTC)