8b41038be7
- Salvage analysis of K501U components - Orange Pi 5 SBC selection rationale - Storage architecture (SD card + USB) - USB hub expansion plan - Parts list and cost estimates
182 lines
No EOL
4.8 KiB
Markdown
182 lines
No EOL
4.8 KiB
Markdown
# Storage Architecture
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**Strategy:** SD card for boot/root, USB for data
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---
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## Design Principles
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1. **Simplicity:** SD card boots out of the box, no U-Boot complexity
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2. **Reliability:** Endurance-rated SD cards last longer
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3. **Flexibility:** USB storage can be swapped/upgraded easily
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4. **Cost:** Minimal investment, repurpose existing drives
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---
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## Layer 1: Boot/Root (MicroSD)
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### Card Selection
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| Attribute | Recommendation |
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|-----------|----------------|
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| Capacity | 64GB minimum, 128 GB preferred |
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| Type | Endurance-rated or Industrial |
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| Brands | SanDisk Endurance, Samsung PRO Endurance |
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**Why endurance cards:**
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Consumer SD cards are rated for bursts of writes (camera use). OS usage is constant logging, updates, cache writes. Endurance cards are rated for:
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- 5000+ hours of continuous recording
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- 1000+ write cycles per sector
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- 5-10× longer lifespan than consumer cards
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**Cost:**$10-15 for 64GB
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### Boot Configuration
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Default Orange Pi 5 boots from SD:
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```
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/dev/mmcblk0 (SD card)
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├── /dev/mmcblk0p1 → /boot (fat32, ~200MB)
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├── /dev/mmcblk0p2 → / (ext4, ~60GB)
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└── /dev/mmcblk0p3 → /home (ext4, remaining)
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```
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Or single partition with separate mount points:
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```
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/dev/mmcblk0p2 → / (ext4, all space)
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/home → bind mount or subdirectory
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```
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### Root-on-USB (Optional)
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For faster I/O, copy root to USB SSD:
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1. Boot from SD, insert USB SSD
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2. `sudo rsync -ax / /mnt/usb/`
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3. Edit `/boot/extlinux/extlinux.conf`:
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```
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append root=/dev/sda1
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```
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4. Boot from USB, SD only handles bootloader
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**Tradeoff:** More complexity, faster app loading.
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---
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## Layer 2: Data Storage (USB)
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### Options
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| Option | Speed | Cost | Notes |
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|--------|-------|------|-------|
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| USB flash drive | 100-150 MB/s | $12-20 | Cheap, limited endurance |
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| USB 3.0 SATA enclosure | ~400 MB/s | $10-15 + drive | Reuse 2.5" drives |
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| USB 3.0 NVMe enclosure | ~400 MB/s | $8-15 + drive | Compact, fast |
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| USD 3.0 flash drive (fast) | 200-400 MB/s | $20-40 | Kingston DataTraveler, Samsung BAR |
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### Recommendation
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**USB 3.0 SATA enclosure with salvaged 2.5" SSD.**
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If you have a spare 2.5" SATA SSD from another build/upgrade:
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- Enclosure cost: $10-15
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- Speed: ~400 MB/s (SATAIII limit over USB 3.0)
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- Capacity: whatever the drive is
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If no spare drive:
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- USB 3.0 flash drive (128GB): $15-25
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- Or NVMe enclosure ($10) + budget NVMe drive ($20-30)
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### Mount Strategy
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```bash
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# /etc/fstab
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UUID=<ssd-uuid>/mnt/data ext4 defaults,noatime 0 2
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/mnt/data/projects /home/jez/projects none bind 0 0
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/mnt/data/media /home/jez/media none bind 0 0
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```
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Mount on-demand or at boot, depending on use case.
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---
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## Storage Layout
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```
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┌─────────────────────────────────────┐
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│ MicroSD Card (/dev/mmcblk0) │
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│ SanDisk Endurance 64GB │
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│ ├── /boot (fat32, 200MB) │
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│ ├── / (ext4, 25GB) │
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│ └── /home (ext4, 38GB) │
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│ Basic config, small files │
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└─────────────────────────────────────┘
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┌─────────────────────────────────────┐
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│ USB SSD (/dev/sda) │
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│ SATA or NVMe in USB 3.0 enclosure │
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│ ├── /mnt/data/projects │
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│ ├── /mnt/data/media │
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│ └── /mnt/data/backup │
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│ Mounted on-demand │
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└─────────────────────────────────────┘
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```
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---
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## Backup Strategy
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### SD Card Imaging
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```bash
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# Backup
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sudo dd if=/dev/mmcblk0 of=cyberdeck-sd-backup.img bs=4M status=progress
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# Restore
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sudo dd if=cyberdeck-sd-backup.img of=/dev/mmcblk0 bs=4M status=progress
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```
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Or use **Pi Imager** / **BalenaEtcher** for GUI imaging.
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### Data Backup
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- Timeshift for system snapshots
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- rsync to external drive
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- Cloud sync for critical files
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---
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## Performance Expectations
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| Operation | SD Card | USB SSD |
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|-----------|---------|---------|
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| Boot time | 8-12s | 5-8s (root-on-USB) |
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| App launch | 1-3s | 0.5-1s |
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| File read (1GB) | 40-90s | 3-5s |
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| File write (1GB) | 60-120s | 3-5s |
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| Random I/O | Slow | Fast |
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**SD card is fine forOS and light use. USB SSD for anything I/O intensive.**
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---
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## Cost Summary
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| Item | Low | High |
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|------|-----|------|
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| MicroSD 64GB Endurance | $10 | $15 |
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| USB 3.0 SATA enclosure | $10 | $15 |
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| (Assume spare SSD) | $0 | $0 |
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| **Total** | **$20** | **$30** |
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If no spare SSD:
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| Item | Low | High |
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|------|-----|------|
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| MicroSD 64GB Endurance | $10 | $15 |
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| USB 3.0 flash drive 128GB | $15 | $25 |
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| **Total** | **$25** | **$40** | |