linux-ext4 - Generic questions about ext4

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Date:   Mon, 17 Aug 2020 03:54:29 +0000
From:   Rogério Brito <rbrito@....usp.br>
To:     linux-ext4@...r.kernel.org
Subject: Generic questions about ext4

Dear developers,

I have been using ext4 for quite some time and I have some ext4
filesystems that led me to some questions.

I have at least 2 "large" filesystems (with 2TB each, both almost
full) dating back from 2011 and 2010. I believe that I even converted
one of them from ext3 to ext4, but my memory is not that clear after
almost a decade. As such, they were created without some useful
features that are useful nowadays, like inline files. With that in
mind, here are some questions:

1 - I know that some features can be enabled with tune2fs, but, in
particular, inline files don't seem to be. I've seen some people
indicate that using debugfs, I can mark the superblock as having
support for it. Would that really work? I don't plan on booting old
kernels. One of those filesystems is running on an armel device that
is quite slow and I would really like to avoid copying all the files
to an external HD, recreating the filesystem and, then, copying back
the files to the system.

2 - Is there any way to get transparent compression with ext4? That
would really, really rock and is, perhaps, one of the features that
some users like me would greatly benefit from.

Thanks for any pointers,

Rogério Brito.

-- 
Rogério Brito : rbrito@...e.usp.br,gmail.com} : GPG key 4096R/BCFCAAAA
http://cynic.cc/blog/ : github.com/rbrito : profiles.google.com/rbrito
DebianQA: http://qa.debian.org/developer.php?login=rbrito%40ime.usp.br