The Western Digital WDMERC4000TN (WDMERC4000TN - Western Digital My Passport Essential 400GB USB 2.0 2.5-inch External Hard Drive) is a External Hard Drive component engineered for sustained enterprise-class workloads. This part addresses common procurement scenarios where exact-match replacement, capacity expansion, or new-build deployment is required. Technical specifications include capacity of 400 GB, form factor of 2.5-inch, interface of USB 2. Common deployment scenarios include database transaction-log volumes, virtualization datastores, OS-boot tier, backup-repository targets, and warm-data tiers in tiered-storage architectures. Pro Disk Network sources the WDMERC4000TN through reputable distribution channels and applies a verification check against the OEM compatibility matrix before each unit is added to active inventory. Each unit ships from a US fulfillment hub (Hillsboro OR, Atlanta GA, or Phoenix AZ) with same-day dispatch on in-stock orders before 3pm ET. 90-day Pro Disk Network functional warranty included; free US ground shipping on orders over $150.
The WDMERC4000TN is a Western Digital external hard drive component with capacity 400 GB, form factor 2.5-inch, interface USB 2. Pricing on the WDMERC4000TN is quote-based — email sales@prodisknetwork.com or use our live chat for a quote within one business day.
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Reviewed by:Pro Disk Network Engineering Team — . Specifications, compatibility, and pricing for the WDMERC4000TN are shown on this page.
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Quick Answer: Will the WDMERC4000TN work with my RAID controller?
The WDMERC4000TN operates with any standard SAS/SATA/NVMe-compatible RAID controller (Dell PERC, HPE Smart Array, LSI/Broadcom MegaRAID, Adaptec, IBM ServeRAID, Lenovo ThinkSystem RAID). Mixing this drive in the same RAID volume with drives of different speed/capacity is supported but never recommended.
How fast does the WDMERC4000TN ship?
If in stock, the WDMERC4000TN ships same business day on US orders placed before 3 pm ET. Most US ZIP codes receive next-business-day or 2-day delivery via FedEx/UPS Ground or Express. Bulk and project orders shipping in pallets are typically dispatched within 24-48 hours.
The WDMERC4000TN is deployed by US enterprises, MSPs, government, and education customers across multiple infrastructure scenarios. Below are the most common deployment patterns Pro Disk Network sees in real-world orders.
VMware vSAN Capacity Tier — Used as bulk storage in all-flash and hybrid vSAN clusters. Pair with NVMe cache-tier drives for SLA-grade write throughput at half the cost of all-NVMe.
Veeam Backup Repository — Cost-optimised backup target for Veeam B&R, Rubrik, or Cohesity primary backup tier. RAID 6 over 8–24 drives delivers 100+ TB usable per server.
Splunk Warm/Cold Tier — Appropriate for Splunk warm/cold/frozen indexes where ingest write rates are below 200 MB/s per node. Avoid for hot-tier indexes — use NVMe instead.
File Server / SMB Shares — General-purpose Windows Server / Samba shares for departmental file storage. RAID 5 for capacity, RAID 10 for IOPS-sensitive workloads.
What is the WDMERC4000TN?
The WDMERC4000TN is a Western Digital enterprise-grade hard drive with capacity 400 GB and form factor 2.5-inch, manufactured by Western Digital. Pro Disk Network ships this part new and certified-refurbished from our US warehouse with same-day dispatch on orders placed before 3 PM ET, backed by a 30-day return guarantee.
Pros & Cons of WDMERC4000TN
Pros
Same-day US shipping from our US warehouse
Cons
Not enterprise NVMe — sub-100 µs latency workloads need a different SKU
Bulk capacity is the value play, not raw IOPS
Larger orders may ship via LTL freight (signature required)
Frequently Asked Questions about WDMERC4000TN
Is the WDMERC4000TN a genuine Western Digital part?
Yes. Pro Disk Network sources every WDMERC4000TN as factory-original Western Digital inventory. New units arrive sealed in OEM packaging; refurbished units are pulled from decommissioned Western Digital servers, surface-tested, and re-warranted by Pro Disk Network for 90 days.
Will the WDMERC4000TN work with my RAID controller?
The WDMERC4000TN operates with any standard SAS/SATA/NVMe-compatible RAID controller (Dell PERC, HPE Smart Array, LSI/Broadcom MegaRAID, Adaptec, IBM ServeRAID, Lenovo ThinkSystem RAID). Mixing this drive in the same RAID volume with drives of different speed/capacity is supported but never recommended.
How fast does the WDMERC4000TN ship?
If in stock, the WDMERC4000TN ships same business day on US orders placed before 3 pm ET. Most US ZIP codes receive next-business-day or 2-day delivery via FedEx/UPS Ground or Express. Bulk and project orders shipping in pallets are typically dispatched within 24-48 hours.
What is the warranty on the WDMERC4000TN?
New WDMERC4000TN units carry the full Western Digital manufacturer warranty (typically 1 to 5 years depending on product line). Refurbished and bulk-OEM units include a Pro Disk Network advance-replacement warranty (90 days refurbished). DOA replacement is free within 30 days of receipt.
Do you offer bulk pricing for the WDMERC4000TN?
Email sales@prodisknetwork.com with the quantity and target ship date for a quote within one business day.
Pro Disk Network Buyer’s Guide: External Hard Drive
How to Pick the Right Drive Capacity for Your Use Case
Sizing a storage drive correctly is the difference between a system that runs predictably for five years and one that you replace under emergency conditions at 18 months. For the WDMERC4000TN, plan capacity around three numbers: working-set size, retention window, and overhead headroom. Working set is the actively-read data — databases, indexes, hot files. Retention window is how long you keep cold data online before tiering off. Overhead headroom should be 25-30%: drives run noticeably slower above 80% utilisation and metadata operations stall above 90%.
Drive Health Monitoring: SMART, Workload Rating, and Predictive Failure
Workload rating — expressed as TB written per year — matters more than raw capacity in choosing the WDMERC4000TN for sustained-write workloads. Consumer SATA drives are rated for 55 TB/year; enterprise SATA for 180-550 TB/year; enterprise SAS for 550 TB+/year; mixed-use NVMe for 1-3 PB/year over five years. Match the rating to your sustained write profile, then add 30% headroom.