[lustre-discuss] Correct use of "lctl get_param health_check"

[Aurelien Degremont]

Hi Dominic,

If health_check returns an error, there is something bad.
If health_check returns healthy, run more checks.

This is more like required, but not sufficient.

It catches errors reported by Lustre targets, but that's all.

Aurélien
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De : lustre-discuss <lustre-discuss-bounces at lists.lustre.org> de la part de Dominic Sloan-Murphy via lustre-discuss <lustre-discuss at lists.lustre.org>
Envoyé : jeudi 11 juin 2026 15:21
À : lustre-discuss at lists.lustre.org <lustre-discuss at lists.lustre.org>
Objet : [lustre-discuss] Correct use of "lctl get_param health_check"

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Hi all,

Would you be able to advise on the correct use of the "lctl get_param health_check" command from https://wiki.lustre.org/Lustre_Health_Checks and under which circumstances it reports errors?

I've found it always returns "healthy", even when I intentionally break my test setup. For example, removing Lustre mounts:

root at lustre-build:~# mount -t lustre mytestpool/mgsmdt /mnt/mgs_mdt
root at lustre-build:~# mount -t lustre ostpool/ost1 /mnt/ost
root at lustre-build:~# lctl get_param health_check
health_check=healthy
root at lustre-build:~# umount /mnt/ost
root at lustre-build:~# lctl get_param health_check
health_check=healthy
root at lustre-build:~# umount /mnt/mgs_mdt
root at lustre-build:~# lctl get_param health_check
health_check=healthy

My setup is a single Ubuntu 24.04 VM with Lustre 2.17 built from source. The Lustre file system was created with:

root at lustre-build:~# truncate -s 5G /root/mgs_mdt.img
root at lustre-build:~# truncate -s 10G /root/ost.img
root at lustre-build:~# mkfs.lustre --mgs --mdt --backfstype=zfs --fsname=mytestfs --index=0 mytestpool/mgsmdt /root/mgs_mdt.img
root at lustre-build:~# MGS_IP=$(hostname -I | awk '{print $1}')
root at lustre-build:~# mkfs.lustre --ost --backfstype=zfs --fsname=mytestfs --mgsnode=${MGS_IP}@tcp0 --index=0 ostpool/ost1 /root/ost.img

Regards,
Dominic
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Dominic Sloan-Murphy

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