Hi all,

We run Qlustar 14 with the standard Spack "HPC Core Stack" setup (softadm
group, /srv/apps NFSv3 export, diskless netboot compute nodes). We ran into
a reproducible issue that we tracked down fully and wanted to share, since
it doesn't seem to be documented anywhere and may affect other sites with
the same standard layout.

## Symptom

After `spack install <pkg>` completes on the head node, the new package is
correctly visible via `spack find` on the head node immediately, but stays
INVISIBLE from `spack find` on compute nodes for an unpredictable amount of
time — anywhere from hours to several days. Raw reads of
`.spack-db/index.json` on the affected compute node (via `grep`/`cat`) show
the file IS up to date at the filesystem level (correct mtime/size/content),
but `spack find` on that same node, at that same moment, still returns the
stale package list. So it isn't a filesystem staleness problem in the usual
sense — the data is there and correct, but the client's NFS session serving
it isn't being refreshed. ..................