On Thu, 3 Feb 2022 16:31:08 +0000
Andy Smith <andy@strugglers.net> wrote:

> Hi,
> 
> I have a host with an xfs filesystem on it, with about 25 million
> files. It contains an rsnapshot backup that has been aggressively
> deduplicated by means of hardlinks and there's probably only about 7
> million unique files on there.
> 
> I'm trying to rsync it to a different host into a btrfs filesystem,
> but part way through the rsync I get a "Too many links (31)" error:
> 
> rsync: [generator] link "/data/backup/rsnapshot/daily.0/chacha/var/lib/dpkg/info/.apt-utils.postrm.0" => daily.0/backup1/var/lib/dpkg/info/libpango1.0-0.postrm failed: Too many links (31)
> Hlink node data for 219191 already has path=daily.0/backup1/var/lib/dpkg/info/libpango1.0-0.postrm (daily.0/chacha/var/lib/dpkg/info/apt-utils.postrm)
> rsync error: errors with program diagnostics (code 13) at hlink.c(539) [generator=3.2.3]
> 
> I searched around on this topic and found hits from 10 years ago
> about maximum hardlinks per directory and being dependent upon
> length of file path. Is that still relevant today?
> 
> [...]
> 
> Is there anything I can do to get this working?

Hello, Have you tried the "extended_iref" mount option? 

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