ZFS: txg_sync stuck at 100% while copy large dataset with rsync

ZFS: txg_sync stuck at 100% while copy large dataset with rsync

While transfering a large dataset (2TiB) via rsync from ext4 to zfs, rsync hangs at some time and txf_sync stuck at 100% cpu.

It was a fresh system and zfs was set up just a few minutes ago. After some research, I found out that this problem is related to ARC.

I’ve changed the zfs_arc_min parameter while trx_sync stuck and the system immediately responses.

echo 1073741824 » /sys/module/zfs/parameters/zfs_arc_min

This sets the minimum size (hard limit) for ARC to 1 GiB.

References

https://github.com/zfsonlinux/zfs/issues/3409#issuecomment-283551036

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Hi, I'm Daniel, a software developer, Linux administrator and landscape photographer.

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