When working with Adaptec 6805 controllers (non-E models) using 8x 2TB 5400RPM SATA drives in RAID6 configurations, users frequently encounter unexpectedly slow reconfiguration times. The core issue manifests when:

• Expanding array capacity by adding disks
• Rebuilding after drive failures
• Modifying RAID levels

The observed behavior where progress remains at 0% for extended periods (35+ hours in your case) typically stems from:

# Common causes in priority order:
1. Background initialization priority (BIOS setting)
2. Drive spin-up latency (5400RPM factor)
3. Controller cache policy configuration
4. MiniSAS lane distribution issues
5. RAID6 double parity calculation overhead

For immediate improvement, try these CLI commands via arcconf (Adaptec's utility):

# Force foreground initialization (immediate start)
arcconf TASK START 1 INITIALIZE 0

# Disable read caching during rebuild
arcconf SETCACHE 1 0 0 0 0

# Set rebuild priority to high
arcconf SETREBUILDPRIORITY 1 HIGH

Given your 8-drive RAID6 setup, consider these architectural adjustments:

# Recommended stripe size for large drives
arcconf SETSTRIPESIZE 1 256

# Disable media patrol during rebuild
arcconf MEDIAPATROL 1 DISABLE

# Verify physical disk alignment
arcconf GETPERFORMANCE 1 PHYSICALDRIVE 0

For automated monitoring, use this Python snippet with pySMART:

import time
from adaptec import controller

ctrl = controller.Adaptec6805()
while True:
    status = ctrl.get_rebuild_status()
    print(f"Progress: {status.percent}% | Rate: {status.mb_sec}MB/s")
    if status.percent == 100:
        break
    time.sleep(300)  # Check every 5 minutes

If rebuild times remain unacceptable after optimization:

• Upgrade to 7200RPM or enterprise drives
• Consider RAID10 instead of RAID6 for better rebuild performance
• Evaluate Adaptec 6805E (with cache memory) for your workload

When working with the Adaptec 6805 controller (non-E variant) and eight Hitachi 2TB 5400RPM drives, RAID reconstruction behavior requires careful analysis. The observed 35-hour delay for just 1% progress indicates either a hardware limitation or configuration issue.

# Sample monitoring command for Linux users
while true; do
    arcconf GETCONFIG 1 LD | grep -i "rebuild progress"
    sleep 300
done

• Drive Speed: 5400RPM drives inherently limit rebuild speed versus 7200RPM or SSD alternatives
• Controller Priority: Adaptec's background task prioritization may throttle rebuilds
• Stripe Size: Suboptimal stripe configurations dramatically impact performance

To properly evaluate rebuild performance:

# Force a rebuild scenario (TEST ONLY - backup first!)
arcconf TASK START 1 DEVICE  TYPE reconstruct

# Monitor controller load
arcconf GETSTATUS 1 | grep -i "controller busy"

Three proven methods to accelerate rebuilds:

1. Increase reconstruction priority in Storage Manager
2. Adjust stripe size during initial array creation
3. Disable background media scans during rebuild