As developers, we deal with critical data daily - source code repositories, database backups, and VM images. Losing 1-2TB of work to a single drive failure can be catastrophic. RAID offers redundancy, but traditional internal solutions often don't fit mobile development workflows.

For external setups, consider these options:

• RAID 1 (Mirroring): Simplest redundancy, 50% capacity efficiency
• RAID 5: Balances capacity and redundancy (needs 3+ drives)
• RAID 10: Best performance but requires 4 drives

Hardware options:
USB RAID enclosures like Mediasonic ProBox (supports RAID 0/1/5/10)
Thunderbolt DAS units for high-performance needs

Software solutions:
Linux mdadm example:

# Create RAID 1 array
sudo mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc

Using diskutil for RAID 1:

diskutil appleRAID create mirror MyRAID1 JHFS+ disk1 disk2

PowerShell example for mirrored storage:

New-VirtualDisk -StoragePoolFriendlyName "ExternalPool" 
-FriendlyName "CodeBackup" 
-ResiliencySettingName Mirror 
-Size 1TB

USB 3.0/3.1 Gen2 provides sufficient bandwidth for most RAID 1/5 setups. For RAID 10 or high-IOPs workloads, consider Thunderbolt 3 enclosures.

Bash script to check RAID status:

#!/bin/bash
RAID_STATUS=$(cat /proc/mdstat)
if [[ $RAID_STATUS == *"UU"* ]]; then
    echo "RAID healthy"
else
    echo "RAID degraded!" | mail -s "RAID Alert" admin@example.com
fi

Best bang-for-buck drives for RAID:

• WD Elements 2TB (shuckable for some enclosures)
• Seagate Expansion Desktop (good for RAID 5)
• Samsung T5 SSD (for performance-critical RAID 1)

Remember RAID isn't backup. Implement the 3-2-1 rule:

• 3 copies of data
• 2 different media types
• 1 offsite copy

Consider combining RAID with cloud backup solutions like rclone to AWS S3 or Backblaze B2.

When working with external drives in RAID configurations, we're typically dealing with USB 3.0/3.1/Thunderbolt or eSATA interfaces. The interface bottleneck becomes crucial when considering RAID types:

// Example Linux mdadm command for RAID1
sudo mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc

RAID 1 (Mirroring): Ideal for 2-drive setups where data redundancy is critical. Write performance equals single drive, read performance can reach nearly 2x.

RAID 5: Requires minimum 3 drives, offers better storage efficiency (n-1 capacity) while maintaining single-drive fault tolerance.

For external setups, software RAID often provides better flexibility:

# Windows Storage Spaces PowerShell example
New-VirtualDisk -StoragePoolFriendlyName "ExternalPool" 
                -FriendlyName "RAID5Array" 
                -UseMaximumSize 
                -ResiliencySettingName Parity 
                -ProvisioningType Fixed

USB 3.0's 5Gbps theoretical limit means even RAID0 may not saturate the interface with HDDs. Benchmark your setup:

// Linux disk benchmark command
hdparm -tT /dev/md0

When a drive fails in RAID1:

1. Identify failed drive: mdadm --detail /dev/md0
2. Remove drive: mdadm --remove /dev/md0 /dev/sdb
3. Replace physically and re-add: mdadm --add /dev/md0 /dev/sdb