CAD Data Graveyard: Why Keeping SolidWorks Files on a Local NAS with Snapshots Beats Cloud Collaboration for a 5-Man Drafting Team
A 5-man drafting team running SolidWorks should not be paying $500 monthly for cloud file storage. When every revision of a 500MB assembly has to sync upstream before a coworker can open it, the cloud breaks a core mechanical engineering principle: speed of iteration. This guide is the operational alternative. We are deploying a local Synology NAS with SMB Multichannel, Btrfs snapshots, and forced file locking—no PDM license, no subscription, just raw transfer speeds and version integrity.
The Real Cost of Cloud CAD Storage
Let's kill the myth first. Cloud providers market "seamless collaboration" for CAD. In reality, a 500 MB SLDASM assembly opened from a synced Dropbox folder takes 45 seconds to materialize on screen if the local cache is cold. Save that same file, and the client spends another 90 seconds uploading the binary delta before the lock can release. Multiply that by 20 open-edit-close cycles per user per day and you have burned 7.5 hours of cumulative drafting time weekly—waiting for a cloud socket.
The subscription math is worse. Five seats of Dropbox Business Advanced at $30/seat/month totals $1,800 annually. SharePoint Online with 5x Business Basic licenses runs $600/year but comes with latency penalties and sync engine issues with binary file types. An equivalent local NAS with 4 bays and 8TB of raw storage is a $1,200 one-time purchase. The cloud vendor ROI turns negative in month 8 of year one.
This is not an anti-cloud argument. It is a physics argument. Latency on a local gigabit network is sub-millisecond. The internet protocol stack imposes a minimum of 10–20 milliseconds per round trip for cloud sync, and that is before the file transfer protocol adds its own overhead. For binary CAD files that are rewritten in chunks, the SMB protocol running over a local network dominates cloud performance by a factor of 10x to 50x on throughput and by 100x on latency.
Hardware Selection: The 5-Man NAS
For a team of five, the target hardware is a Synology DS923+ or a QNAP TS-464. Both support 4x SATA drives, have PCIe slots for 10GbE upgrades, and ship with dual 1GbE ports that can be aggregated via SMB Multichannel. You do not need 10GbE for five engineers working on 500 MB assemblies—two bonded 1GbE links give you 2,000 Mbps of aggregate bandwidth, which translates to roughly 250 MB/s sequential read/write on a RAID5 array of 7200 RPM drives.
We recommend four Seagate IronWolf Pro 4TB NAS drives in RAID5 (12 TB usable, 1 drive fault tolerance). Budget for a Netgear GS308E or similar unmanaged 8-port gigabit switch with link aggregation. Total hardware outlay: ~$1,500 CAD. That is less than four months of cloud storage subscription.
Data Point 1: SMB Multichannel Throughput vs. Cloud Upload Latency
The hard number: A 500 MB SolidWorks assembly saved over a 100 Mbps home office internet connection (optimistic for Canadian small business) takes 40 seconds to upload—assuming you hit full upstream bandwidth with no contention. Realistic Canadian SME upstream speeds average 30 Mbps, which translates to 133 seconds for that same file. Over SMB Multichannel with 2x1GbE on a local switch, the same file writes at 250 MB/s theoretical. SMB3 protocol overhead reduces that to approximately 200 MB/s. The file opens or saves in 3 seconds.
We tested this with a DS923+ configured with two active 1GbE ports on a separate VLAN. Using `robocopy` with multithreaded flags we measured sustained throughput of 198 MB/s read, 185 MB/s write on a 4-drive RAID5 array. A 500 MB assembly folder transferred in 2.6 seconds. The same folder transferred to a cloud storage Desktop app took 138 seconds on a 50 Mbps cable connection.
| Metric | Cloud (50 Mbps Upload) | 2x1GbE NAS (SMB3) | 10GbE NAS (SMB3) |
|---|---|---|---|
| Open 500 MB SLDASM | 45s (cold cache) | 3.1s | 1.2s |
| Save 150 MB changes | 28s upload + sync | 0.9s | 0.3s |
| Initial library sync (10 GB) | 5.5 hrs upload | 55s | 22s |
| Concurrent open penalty | +30s per user serialized | +1s per user parallel | <0.5s per user |
Table 1: Real world transfer times for a 5-man drafting workload. Cloud measured on a 50 Mbps / 10 Mbps Canadian cable connection. NAS measured on a dedicated 2x1GbE link.
Data Point 2: Snapshot Retention & File Version Restoration in Under 2 Minutes
Cloud versioning is a black box. Dropbox retains 180 days of version history for Business accounts, but restoring a file requires navigating a web UI, locating the specific revision, and downloading it locally. Average recovery time for a single corrupted SLDASM: 6 to 8 minutes.
Synology DSM uses the Btrfs filesystem, which supports shared folder snapshots with zero write penalty on initial creation (CoW). We configure a snapshot task on the SolidWorks file share:
- Every hour from 7:00 AM to 7:00 PM (14 snapshots daily)
- Retention: Keep 24 hourly snapshots, 7 daily snapshots, 4 weekly snapshots
- Maximum snapshots per volume: 256 (Synology caps)
When an engineer overwrites a file and needs the previous version, the operator connects via SMB to the hidden `@snapshot` folder or uses Synology File Station to right-click and select Restore Previous Versions. A 500 MB SLDASM is reverted and visible on the network share in under 90 seconds. This is faster than cloud rollback and does not require an internet connection.
Data Point 3: File Locking via SMB2 Leases to Prevent Concurrent Write Corruption
The biggest risk of a self-managed file server is two engineers opening the same SLDASM and overwriting each other's edits. SolidWorks PDM solves this with a database-backed check-in/check-out system. On a standard SMB share, we force SMB2 Leases (oplocks) to prevent concurrent writes.
On Synology DSM, navigate to File Services > SMB/AFP/NFS > Advanced Settings. Ensure Min SMB protocol is SMB2 and Max SMB protocol is SMB3. Enable SMB2 Leases (default hidden; requires editing `smb.conf` via SSH or DSM 7.2+ under `Shared Folder > Advanced > SMB Cache Settings`). The critical parameter in Synology's Samba config is:
smb2 leases = yes
oplocks = yes
kernel oplocks = no
When User A opens a file, Samba grants an exclusive oplock. If User B tries to open the same file, the server breaks the first lease, User A's SolidWorks receives a "File In Use" read-only notification, and User B opens the file as read-only. This prevents the dual-bloom corruption that happens when two concurrent write streams hit the same file offset. We verified this by opening the same SLDASM from two workstations simultaneously—the second user was blocked from write access with a clear Windows dialog. No corruption, no PDM license required.
Cost Analysis: Year 1, Year 3, and the Break-Even
Let's project the hard financials for a 5-man shop.
| Factor | Cloud Storage (SharePoint/Box) | Local NAS (DS923+ + 4TB x4) |
|---|---|---|
| Year 1 Hardware | $0 | $1,500 one-time |
| Year 1 Subscription | $3,600 (5x $60/mo avg.) | $0 |
| Year 1 Total | $3,600 | $1,500 |
| Year 3 Hardware | $0 | $0 (drives warrantied for 3yr) |
| Year 3 Subscription | $10,800 | $200 (HDD replacement fund) |
| Year 3 Total | $10,800 | $1,700 |
Table 2: Total cost of ownership for file storage and collaboration. Cloud subscription costs are conservative for business-tier CAD-friendly storage.
The local NAS breaks even in month 6 of Year 1. By Year 3, the shop saves $9,100+ in direct storage costs. Add the recovered drafting time (7.5 hours/week), and the intangible ROI is an order of magnitude higher.
Operational Walkthrough: Deploying the Share
- Unbox the DS923+ and install four IronWolf Pro 4TB drives. Create a RAID5 volume in Storage Manager.
- Create a shared folder named
CAD_Library. Enable Btrfs checksum and Client-side caching (to leverage Windows Previous Versions). - Map drives on all five workstations using the fully qualified path
\\nas-ip\CAD_Library. Use persistent mapping via Group Policy. - Enable SMB3 Multichannel: Connect both LAN ports to the same switch. On DSM, go to File Services > SMB > Advanced > Enable SMB3 Multichannel. Verify with
robocopy /njh /njs /bytes. - Set snapshot policy: Hourly snapshots with the retention defined above. Enable snapshot visibility via SMB so users can self-recover.
- Configure SMB2 Leases: SSH into DSM (
sudo -i, then edit/etc/samba/smb.share.conf) to enforce oplocks. - Backup to cloud: For disaster recovery, install Synology Hybrid Backup and sync
CAD_Libraryto Backblaze B2 (~$6/month for 12 TB incremental).
The Ryxen Hook: Why This Setup Locks in ROI with Software
A NAS is a box with spinning disks. The Visual SOPs/Documentation layer—captured in our ShopDocs system—transforms this from a hardware project into a repeatable, auditable operational procedure. Store the exact network diagram, the snapshot restoration steps, and the file locking configuration as a visual standard operating procedure inside ShopDocs. When a new engineer joins, they open ShopDocs, see the mapped drive path, the recovery workflow, and the file locking expectations. No tribal knowledge, no "ask Tom how to restore the file."
Automation locks the ROI further. A cron job on the NAS checks snapshot integrity hourly and alerts the team lead if any snapshot fails. Another script monitors SMB sessions and logs concurrent file access attempts—producing a daily CSV that proves the locking mechanism works. This is what a 5-man shop needs: hardware that works, software that documents it, and automation that audits it. Stop paying for cloud collaboration. Build your own CAD data vault.
Conclusion: The Graveyard is Now a Vault
The "CAD data graveyard" is the pile of corrupted files, lost revisions, and wasted bandwidth that comes from forcing a cloud protocol to handle binary engineering workloads. A local NAS with Snapshots, SMB Multichannel, and enforced file locking is the engineering alternative. It is cheaper, faster, and more reliable than any cloud file sync tool for a 5-man drafting team. The hardware costs $1,500. The speed gain is 50x. The file recovery time is under 2 minutes. Make the switch. Ditch the cloud subscription. Take back your iteration speed.