linux-ext4 - Re: Why isn't ext2 deprecated over ext4?

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Message-ID: <20240222201252.GA744192@mit.edu>
Date: Thu, 22 Feb 2024 15:12:52 -0500
From: "Theodore Ts'o" <tytso@....edu>
To: Reindl Harald <h.reindl@...lounge.net>
Cc: linux-ext4@...r.kernel.org
Subject: Re: Why isn't ext2 deprecated over ext4?

On Wed, Feb 21, 2024 at 11:57:22PM +0100, Reindl Harald wrote:
> 
> Fedora for sure didn't invent the nonsense in "mke2fs.conf" falling back to
> such pervert settings for very small martitions

So first lf all, "very small" means "smaller that 512 megs".  The
rationale was to reduce the overhead for small thumb drives, where
maximizing space for data files was considered most important.

In practice, most root file systems tend to be larger than 512 megs.
For example, the absolute minimum EBS size in Amazon's cloud is 1GiB
for General Purpose SSD backed EBS, and 5GiB for HDD backed EBS.
Google Compute Engine's minimum Persistent Disk size is 10 GiB.

In any case, starting in e2fsprogs 1.46.4 (released August 2021, first
shipped in Fedora 36), we changed the default so that 256 byte inodes
is used everywhere, including these small file systems.

If you didn't like the old default, well, for these really small file
systems, the good news is that it's pretty simple to backup, reformat,
and restore the file system.  (And of course, when the root file
system is that small, in general reinstalling it is no big deal.)

Cheers,

					- Ted