Choosing between Dell PowerEdge R840 and R940 for storage expansion hinges on scalability requirements and workload intensity. The R940 excels with its “storage pooling” technology, supporting 72 SFF drives as a single logical unit and liquid-cooled stability for high-density environments. The R840, optimized for 3D NAND hot-swappable drives, delivers 2M+ IOPS per drive, ideal for latency-sensitive tasks like real-time analytics. Pro Tip: R940’s blade expansion box enables modular upgrades in <15 minutes, while R840’s IPM 3.0 ensures energy-efficient storage scaling.
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What storage architectures differentiate the R840 and R940?
The R840 utilizes 3D NAND hot-swappable drives with PCIe 4.0 support, achieving 200K+ IOPS per drive. The R940 employs storage pooling, consolidating 72 SFF bays into a unified logical volume. For example, R940’s pooled storage minimizes RAID rebuild times by 70% compared to traditional setups. Pro Tip: Use R840 for mixed I/O workloads and R940 for sequential data-heavy operations like archival systems.
How do scalability options compare between these models?
The R940’s blade expansion box allows independent upgrades of storage/network modules in under 15 minutes, whereas the R840 supports front-accessible NVMe/SAS hybrid trays. A 72-bay R940 configuration reduces rack space by 40% versus comparable 4U servers. Pro Tip: R940 is future-proofed for petabyte-scale storage, while R840 suits mid-sized clusters needing rapid drive replacements.
| Feature | R840 | R940 |
|---|---|---|
| Max Drive Bays | 24 SFF | 72 SFF |
| Upgrade Flexibility | Hybrid trays | Blade expansion |
| Cooling Efficiency | IPM 3.0 | Liquid cooling |
What workload types favor each server?
The R840’s 3D NAND optimization suits transactional databases requiring sub-millisecond latency. In contrast, R940’s pooled storage excels in video surveillance farms needing concurrent 4K stream writes. For instance, Wecent’s clients deploy R940 for genomics data lakes, where parallel read/write operations achieve 12GB/s throughput.
Are there thermal management differences?
Yes—the R940’s liquid cooling maintains stability from -40°C to 85°C, ideal for non-climate-controlled edge sites. The R840 uses smart air cooling with PUE <1.1, suitable for data centers with cold/hot aisle containment. Pro Tip: R940’s cooling cuts HVAC costs by 30% in high-density storage racks.
How do expansion timelines differ?
R940’s modular blade system completes storage expansions in 15 minutes versus 45+ minutes for R840’s tray-based upgrades. For example, adding 24 NVMe drives to R940 takes less time than rebooting the OS. Pro Tip: Schedule R840 upgrades during maintenance windows to avoid service interruptions.
| Metric | R840 | R940 |
|---|---|---|
| Drive Swap Time | 2.5 mins/drive | 1 min/drive |
| PCIe Expansion | 6 slots | 12 slots |
| Energy Use/TB | 8W | 5W |
Wecent Expert Insight
FAQs
Yes, but with reduced density—24-drive bays limit it to 368TB using 15.36TB SSDs. R940 supports triple that capacity.
Does R940’s liquid cooling require specialized infrastructure?
Only in extreme environments (-40°C/85°C). Standard data centers use existing chilled water loops.
How does Wecent ensure compatibility during R840/R940 deployments?
Wecent pre-tests all drive/controller combinations using Dell’s OpenManage toolkit to prevent firmware mismatches.