This FAQ answers the most common questions from prospects and customers about the Caelum appliance (edited by GaLiLo). Answers are deliberately short and factual. For detailed procedures, see the installation guide and the administration guide.
The product in brief#
What is Caelum?#
Caelum (edited by GaLiLo) is an intelligent NAS storage appliance. It serves SMB (Windows) and NFS (Unix/Linux) file shares, audits them, helps you migrate from an existing NAS, and lets you tier local storage to an object cloud (S3) to archive cold data while keeping transparent access. It ships as an ISO image you install on your own infrastructure (VMware, Proxmox, Hyper-V, KVM, bare-metal).
How is it different from a regular NAS?#
A regular NAS stores and serves files. Caelum does that and adds three things: (1) an audit of your existing data (age, type, volume, archiving candidates); (2) tiering to S3 object storage with transparent recall: an archived file stays visible and opens normally, recalled on the fly; (3) a migration assistant that copies data and access rights from an existing NAS. Caelum is built on a proven base (Debian + ZFS + Samba).
Is Caelum a sovereign cloud?#
No. Caelum does not host your data in a cloud. It is a gateway for access and tiering to the object cloud that YOU choose (AWS S3, a European sovereign S3, MinIO, Wasabi, Backblaze, Ceph, etc.). You keep control of the backend and the contract. Caelum gives you instant local access to data archived in that cloud, without manual re-downloads.
How is it different from a regular cloud gateway?#
A cloud gateway usually just presents an S3 bucket as a share. Caelum works the other way around: your data lives locally (on ZFS), stays fast, and only cold data is offloaded to S3 according to your rules (by last-access age, by file type, per share or per volume). Access stays transparent thanks to automatic recall, and everything is driven from a single interface with audit, snapshots and migration built in.
Sovereignty and data#
Where does my data stay?#
Your files stay on your appliance (your infrastructure). If you enable S3 tiering, the cold files you choose to offload are copied to the object cloud you declared — you pick the location and provider. Caelum does not push any data to a third party without your knowledge.
Does Caelum "phone home"?#
License verification is offline (Ed25519 cryptographic signature, no network call). Minimal, anonymous telemetry can be enabled or disabled at install; it never contains the content of your files. The appliance runs in air-gapped environments (trial and license are handled locally).
Is my data subject to the Cloud Act?#
Your files do not leave your appliance, except toward the object cloud you designate. If you want to stay out of reach of non-European legislation, choose an S3 backend hosted in Europe. Caelum leaves you that choice; it imposes no provider.
Security and resilience#
How does Caelum protect against ransomware and mistakes?#
Caelum relies on ZFS snapshots: consistent, scheduled copies of your volumes from which you can restore a prior state after malicious encryption or accidental deletion. Snapshots are exposed natively to Windows clients as "Previous Versions". You can also serve a share read-only. Combined with the access audit log, this gives you the means to detect, understand and roll back.
How do I expose Windows "Previous Versions"?#
With a single checkbox. On a volume or a share, enable the "Enable Previous Versions" switch: Caelum provisions the whole chain at once (SMB exposure
- auto-managed snapshot schedule). Disabling it cleans everything up. The advanced options (hourly/daily/weekly frequency, number of snapshots kept — 24 by default) stay collapsed. On the workstation side: right-click a file → Properties → Previous Versions.
Is there an access audit log?#
Yes. Caelum keeps an audit log of file operations, useful for traceability, investigations and compliance.
Which high-availability modes does Caelum offer?#
Two, to choose according to your infrastructure:
- Shared storage: a single pool on a multi-writer SAN/iSCSI array, managed by Pacemaker; failover between the two nodes is transparent and lossless (zero RPO). This mode requires shared storage and, in production, a fencing mechanism (STONITH).
- Replication ("Option A"): each node keeps its own local pool, an asynchronous ZFS replication keeps the second node as a mirror. No shared array required, but failover is manual and the RPO equals the replication interval. After a failover, the cloud destination secret must be re-entered on the promoted node, and both nodes must be joined to the domain if your shares use AD accounts.
An assistant guides you and can recommend the mode by detecting a physically shared disk between the two nodes (when the array exposes a stable identifier such as a WWN/serial).
Are communications encrypted?#
The administration interface is served over HTTPS. The certificate is self-signed by default; you can install your own.
Compatibility#
Which sharing protocols are supported?#
SMB (Windows shares) and NFS (Unix/Linux), with a per-share read-only option.
Does Caelum integrate with Active Directory?#
Yes. The appliance joins an Active Directory domain; domain users and groups access the shares with their credentials. LDAP is also supported. You can also manage local accounts.
What can I install it on?#
A single ISO image installs identically on VMware/vSphere, Proxmox VE, Hyper-V, KVM/libvirt and bare-metal. See the requirements in the installation guide.
Which object storage backends are compatible?#
Any S3-compatible object storage: AWS S3, MinIO, Wasabi, Backblaze B2, Ceph, as well as European sovereign S3 offerings. They are declared in the Cloud destinations view.
Can I use a SAN / iSCSI array?#
Yes. Caelum is an iSCSI initiator: from Storage → iSCSI targets, you attach a remote LUN (SAN array, enterprise NAS, Synology…) via its portal (IP:port, 3260), with optional CHAP authentication. The LUN appears as a disk to create or extend a pool. Network-path redundancy is handled by Multipath (MPIO). Disconnecting a target is refused as long as its LUN belongs to an imported pool.
Does Caelum manage several storage pools?#
Yes. There is a primary pool (/galilo/data) and, if needed, additional
pools (/galilo/pools/<name>) — useful to consolidate several arrays or separate
uses. Each volume is placed on the pool of your choice. Note: as it stands,
additional pools operate in standalone mode and do not yet follow a
high-availability failover (which applies to the primary pool).
Does the appliance appear in the Windows network neighborhood?#
Yes, automatically. Caelum announces itself via WS-Discovery (Windows 10/11 "Network" neighborhood) and mDNS/Bonjour (macOS Finder), with no setting to enable.
Migrating from an existing NAS#
Can Caelum migrate my old NAS?#
Yes. The migration assistant copies data from a source share (SMB/NFS) to the appliance. In an Active Directory environment, Caelum strives to faithfully reproduce the domain's NTFS access rights on migrated data. When full reproduction of the rights is not possible (for example without adequate administrative credentials), Caelum falls back to a safe mode that keeps data accessible, without ever opening access beyond what is necessary.
Will I lose my Windows permissions when migrating?#
That is precisely the problem the assistant aims to avoid. Fidelity of the domain's NTFS rights is a core goal of Caelum migration. We recommend validating the result on a sample of shares before switching to production.
Sovereign support AI assistant#
What is the Caelum AI assistant?#
An assistant built into the appliance that answers your administration and getting-started questions based on the product documentation. It is optional: the administrator enables or disables it.
Does the AI see the content of my files?#
No. The assistant only sees commands, metadata and the product documentation context — never the content of your files, which never leave the appliance.
Where are my questions to the assistant processed?#
The Caelum assistant is sovereign, hosted in France. The exchanges (questions and metadata) stay in France (under GDPR, outside the Cloud Act). If the assistant is not configured, it is simply unavailable — there is no fallback to a third-party cloud service.
Licensing and trial#
What license editions exist?#
Four: Free (1 TB, perpetual, free), Trial (30-day trial), Production (subscription) and NFR (internal/partner use, not for resale). Enabled features depend on the license.
How does the trial work?#
The trial starts locally, 30 days, without Internet and without prior registration. On expiry, the appliance switches to a restricted mode; applying a valid license restores access. The trial is protected against system-clock tampering.
Is the license verified online?#
No. The license is validated offline via cryptographic signature. No call to a license server is required to operate.
Updates and support#
How are appliances updated?#
Updates are applied from the interface (System → Updates). The installed version
and the availability of an update are shown in the administration interface. A
pre-update snapshot is taken automatically, with the ability to roll back. In
an air-gapped (no Internet) environment, you can also install from a file
(tarball galilo-update-*.tar.gz).
Is there a pre-release (beta) channel?#
Yes. A beta channel lets testers evaluate new versions early. The stable channel remains recommended for production.