[PATCH] man/man5/core.5: Update compression format for systemd-coredump

[PATCH] man/man5/core.5: Update compression format for systemd-coredump

[Patsy Griffin]

As of version 246, systemd-coredump defaults to zstd compression
for core dumps, rather than lz4.

Signed-off-by: Patsy Griffin <patsy@redhat.com>
---
 man/man5/core.5 | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/man/man5/core.5 b/man/man5/core.5
index 4da5819b6..83c49d42d 100644
--- a/man/man5/core.5
+++ b/man/man5/core.5
@@ -515,9 +515,14 @@ program:
 In this case, core dumps will be placed in the location configured for
 .BR systemd\-coredump (8),
 typically as
-.BR lz4 (1)
-compressed files in the directory
+.BR zstd (1)
+compressed files
+ending in ".zst"
+.\" Since Systemd 246:
+.\" commit ef5924aa313d1892bb491c870ba3c429454dfc76
+in the directory
 .IR /var/lib/systemd/coredump/ .
+Compression on or off is configurable via coredump.conf(5).
 One can list the core dumps that have been recorded by
 .BR systemd\-coredump (8)
 using
-- 
2.51.1

Re: [PATCH] man/man5/core.5: Update compression format for systemd-coredump

[Carlos O'Donell]

On 5/1/26 3:06 PM, Patsy Griffin wrote:
> As of version 246, systemd-coredump defaults to zstd compression
> for core dumps, rather than lz4.
> 
> Signed-off-by: Patsy Griffin <patsy@redhat.com>

LGTM.

I thought coredump.conf allowed you to specify which compression format,
but I was wrong, you can only turn it on or off. This looks correct and on
my system all my coredumps are *.zst today. Best to update this to match
latest deployments.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> ---
>   man/man5/core.5 | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/man/man5/core.5 b/man/man5/core.5
> index 4da5819b6..83c49d42d 100644
> --- a/man/man5/core.5
> +++ b/man/man5/core.5
> @@ -515,9 +515,14 @@ program:
>   In this case, core dumps will be placed in the location configured for
>   .BR systemd\-coredump (8),
>   typically as
> -.BR lz4 (1)
> -compressed files in the directory
> +.BR zstd (1)
> +compressed files
> +ending in ".zst"
> +.\" Since Systemd 246:
> +.\" commit ef5924aa313d1892bb491c870ba3c429454dfc76
> +in the directory
>   .IR /var/lib/systemd/coredump/ .
> +Compression on or off is configurable via coredump.conf(5).
>   One can list the core dumps that have been recorded by
>   .BR systemd\-coredump (8)
>   using


-- 
Cheers,
Carlos.

Re: [PATCH] man/man5/core.5: Update compression format for systemd-coredump

[Alejandro Colomar]

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Hi Patsy, Carlos,

On 2026-05-01T15:08:21-0400, Carlos O'Donell wrote:
> On 5/1/26 3:06 PM, Patsy Griffin wrote:
> > As of version 246, systemd-coredump defaults to zstd compression
> > for core dumps, rather than lz4.
> > 
> > Signed-off-by: Patsy Griffin <patsy@redhat.com>
> 
> LGTM.
> 
> I thought coredump.conf allowed you to specify which compression format,
> but I was wrong, you can only turn it on or off. This looks correct and on
> my system all my coredumps are *.zst today. Best to update this to match
> latest deployments.
> 
> Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Thanks!

> 
> > ---
> >   man/man5/core.5 | 9 +++++++--
> >   1 file changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/man/man5/core.5 b/man/man5/core.5
> > index 4da5819b6..83c49d42d 100644
> > --- a/man/man5/core.5
> > +++ b/man/man5/core.5
> > @@ -515,9 +515,14 @@ program:
> >   In this case, core dumps will be placed in the location configured for
> >   .BR systemd\-coredump (8),
> >   typically as
> > -.BR lz4 (1)
> > -compressed files in the directory
> > +.BR zstd (1)
> > +compressed files
> > +ending in ".zst"

I think this should be added to suffixes(7).

Also, I doubt the suffix should be documented here.  Is it an
uncommon suffix for zstd(1)-compressed files?  If it's the/a common
suffix, it should be enough to document it in suffixes(7) and say it's
zstd(1) here.


Have a lovely night!
Alex

> > +.\" Since Systemd 246:
> > +.\" commit ef5924aa313d1892bb491c870ba3c429454dfc76
> > +in the directory
> >   .IR /var/lib/systemd/coredump/ .
> > +Compression on or off is configurable via coredump.conf(5).
> >   One can list the core dumps that have been recorded by
> >   .BR systemd\-coredump (8)
> >   using
> 
> 
> -- 
> Cheers,
> Carlos.
> 

-- 
<https://www.alejandro-colomar.es>

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