MongoDB container in Nomad with data on SeaweedFS mount hangs

[gutleib]

I'm getting no particular errors, but MongoDB never deploys, and if I transfer database to SeaweedFS mount, it never listens to connections.

Details:

SeaweedFS 3.85 cluster is deployed on 3 VMs, each has Master+Volume+Filer daemons. Filer runs in S3 mode, and uses MariaDB+Galera cluster with daemons run on same 3 VMs. So, it's 3 identicaly configured VMs. Volumes are placed on BTRFS-formatted bcache devices, mounted with noatime and zstd:2 options.
MongoDB (official DockerHub image mongo:8) is deployed in Nomad (v1.9.3) cluster, which has SeaweedFS CSI controllers (chrislusf/seaweedfs-csi-driver:v1.2.7) installed and volumes placed directly on SeaweedFS.
And one more strange detail: if I use upper folder for mount (e.g. /data instead of /data/db) inside container, data does not go to SeaweedFS. I see "db" folder in SeaweedFS via fs.ls in weed shell, but it's empty. And MongoDB works ephemerally then.