Storage Media

EQ Watch records approximately 50 GB of CPOW data per day for a typical 3-phase deployment (losslessly compressed; lighter configurations use less). Each gateway ships with 1 TB (lab) or 1.5 TB (industrial) of storage, providing approximately three weeks to one month of continuous waveform history. This guide explains storage requirements and considerations.

Choice of Storage Hardware

Basic Requirements

• USB storage drive, SD card, or other removable media
• USB port on gateway (USB 3.0 required for optimal performance)
• Minimum write speed of 10 MB/s for CPOW recording

Recommended Features

• Industrial temperature rating (-25°C to 85°C) for harsh environments
• Published endurance ratings (terabytes written, TBW)
• UHS-I or better for optimal performance

Performance Considerations

• Interface speed affects data retrieval and visualization:
  • Use the blue USB 3.0 port on front panel for best performance
  • Back panel USB 2.0 ports will limit transfer speeds
• Sustained write speed affects recording reliability:
  • Minimum required: 10 MB/s (e.g., V10 speed class for SD cards)
  • Recommended: 30 MB/s or better (e.g., UHS-I for SD cards)
• Although CPOW data averages less than 1 MB/s, data is written in batches and derived data may be added during postprocessing

Storage Rotation

EQ Watch automatically manages disk space by removing the oldest CPOW data files when free space drops below 4 GB (configurable). If remote storage is enabled, already-replicated files are removed first. Unsynced files are only removed when necessary.

With ~50 GB per day for a typical 3-phase deployment, 1.5 TB of storage provides approximately one month of local retention before rotation begins. Lighter configurations (fewer active channels) use less storage and retain data longer. If your deployment does not include remote data storage, back up any important data before it is overwritten or in case of media failure.

Storage Endurance

• Cards/drives with published endurance ratings (TBW) are strongly recommended for continuous recording
  • TBW is the product of rated writes per cell and capacity
  • However, actual endurance varies significantly between manufacturers and models
• With a modest 3000 write cycles per cell, endurance varies by capacity:
  • A 64 GB card would last about 10.5 years (64 GB × 3000 ÷ 50 GB/day)
  • A 1 TB card would last about 164 years (1000 GB × 3000 ÷ 50 GB/day)

Included Hardware

Industrial gateways ship with 1.5 TB microSD storage; lab gateways include 1 TB NVMe. For replacements or self-sourced media:

• SanDisk MobileMate USB 3.0 Card Reader (SanDisk part number SDDR-B531-AN6NN)
• SanDisk 1.5 TB Ultra UHS-I microSDXC Memory Card (or 1 TB for lab gateways):
  • Operating temperature -25°C to 85°C
  • V10 speed class (10 MB/s minimum)
  • UHS-I interface
  • 150 MB/s sequential read
  • 10-year manufacturer warranty
  • Write endurance not rated

SanDisk Ultra UHS-I microSDXC Memory Card and MobileMate USB 3.0 Card Reader

Swapping Storage Media

Prerequisites

• New storage media (pre-formatted from Energy Quotient, or bring your own)
• SSH access to gateway if you are using your own storage media

Steps

Picture of gateway including power button, power LED, and SD card with adapter

1. To safely shut down the gateway:

   • Press and hold the power button for 1 second, then release
   • Wait for the LED to turn off (about 2–3 seconds) before proceeding

2. Remove the storage media:

   • For SD cards: Remove card from adapter (may be easier to remove adapter from USB first)
   • For USB devices: Simply unplug from the USB port

3. Insert the new storage media:

   • For SD cards: Insert new card into adapter and reinsert into USB port
   • For USB devices: Plug directly into USB port

4. Press and hold the power button for 1 second to turn the gateway back on.

5. If you are using your own storage media, follow the Storage Media Setup instructions to format and prepare the media.

Storage Media Setup

These instructions are for users who purchase their own storage media rather than using pre-formatted media from Energy Quotient. This process will prepare the media for use with EQ Watch.

1. Check Device

   # Insert SD card into adapter and adapter into gateway's USB port
   ls /dev/sda*
   
   # Confirm that /dev/sda1 exists
   # If not, try:
   # sudo mknod /dev/sda1 b 8 1
   
   # Useful commands for device verification:
   lsblk -o name,uuid,label
   sudo blkid
   

2. Partition and Format

   # Create a new partition table and single partition using all space
   sudo parted -s /dev/sda mklabel gpt
   sudo parted -s /dev/sda mkpart primary ext4 0% 100%
   
   # Format the card with no percentage-based reserved space
   sudo mkfs.ext4 /dev/sda1 -L eqdata -m 0
   
   # Reserve 100MB (25600 4K blocks) for log management
   sudo tune2fs -r 25600 /dev/sda1
   
   # Mount and set up permissions
   sudo mount -a
   sudo rm -r /mnt/eqdata/lost+found/
   
   # Set correct ownership and permissions for synapse group
   sudo chown synapse:synapse /mnt/eqdata
   sudo chmod 2775 /mnt/eqdata
   

3. Verify

   # Check mount points, sizes, and device info
   df
   sudo blkid
   
   # Check filesystem integrity (unmount first)
   sudo umount /dev/sda1
   sudo e2fsck -f /dev/sda1
   sudo mount /dev/sda1 /mnt/eqdata
   

4. Remove or start using the new media

   # To remove the media:
   sudo umount /dev/sda1
   
   # Or to restart and use the new media:
   sudo shutdown -r now