Dell PowerEdge R750 12-Bay 3.5"

The Dell PowerEdge R750 12-Bay 3.5" Hot-Swap is the LFF capacity-tier configuration of Dell's 15th gen 2U flagship rack platform: twelve large-format hot-swap bays for high-capacity NL-SAS or SATA drives alongside the full R750 platform underneath. Up to 240 TB raw at 12 x 20 TB NL-SAS, with dual Ice Lake sockets, 32 DDR4 DIMM slots, PCIe Gen4, and active 15th gen platform currency. This is the R750 variant for capacity-primary workloads: NAS, backup targets, Ceph capacity-tier OSD nodes, and bulk-storage applications where the LFF drive count is the design driver and dual-socket compute is a useful but not primary benefit.

The R750 is current-production at Dell. For LFF capacity at 15th gen platform currency, refurbished R750 12-Bay is the cost-correct call vs. buying new at full list price. For shorter-lifecycle bulk storage where 14th gen platform parity is acceptable, the R740xd 12-Bay 3.5" delivers equivalent storage performance at meaningfully lower cost; we quote both.

For full R750 platform documentation (dual-socket Ice Lake, 32 DIMM slots, PCIe Gen4, PERC H755, HBA355i, BOSS-S2, Optane PMem support), see the canonical R750 16-Bay 2.5" page. This page focuses on what changes at the 12-Bay LFF chassis.

To configure an R750 12-Bay build, call 1-800-778-1545 or request a quote through the form on this page. We respond within 24 hours, and volume pricing applies at 5 units and up. Every unit ships after a 12+ hour burn-in across every drive bay, memory channel, and PCIe slot, backed by our standard 180-day warranty.

What's Different About This Chassis

1. LFF capacity drives only. Twelve 3.5" front bays for SAS or SATA spinning drives, or large-format SAS SSDs in the rare cases where 3.5" SSD makes sense. No NVMe support on the 12-Bay LFF backplane; this configuration is purpose-built for capacity-per-bay, not latency-per-bay.
2. No GPU support. Per Dell's R750 service manual, the 12-Bay 3.5" chassis explicitly does not support GPU cards. The LFF backplane and cabling consume the chassis budget that GPU configurations need. For GPU-capable R750, the canonical 16-Bay 2.5" or 24-Bay 2.5" SFF configurations are the right path.
3. RAID 6 is non-negotiable on large-capacity drives. At 18-20 TB NL-SAS, single-drive rebuild times can exceed 24 hours. RAID 5 with one parity drive leaves the array exposed during that window to a second-drive failure. RAID 6 with two parity drives is the only defensible RAID level for capacity-class NL-SAS arrays at this scale. We will not configure RAID 5 on 14 TB+ NL-SAS without an explicit customer override.
4. Storage controllers stay the same as 16-Bay. PERC H755 with 8 GB flash-backed cache is the production-grade hardware RAID choice. HBA355i for Ceph, ZFS, GlusterFS, and any software-defined storage stack managing its own redundancy.
5. Compute and memory architecture are full R750. 12-Bay LFF does not give up anything on CPU or memory: dual Ice Lake sockets, 32 DIMM slots, up to 4 TB RDIMM or 8 TB LRDIMM. For converged storage + compute nodes (Ceph OSD plus client workloads, NAS with deduplication/compression), the full Ice Lake platform underneath is meaningful.

Storage - 12 LFF Bays

Twelve 3.5" SAS/SATA hot-swap front bays. The R750 12-Bay backplane is SAS/SATA only; no NVMe path.

• NL-SAS HDD (up to 20 TB): The primary use case. 12 x 20 TB = 240 TB raw, approximately 180 TB usable at RAID 6 with one hot spare. Excellent sequential throughput; modest random IOPS. For NAS, backup-to-disk, archive, and warm-tier storage.
• SAS HDD (10K / 15K RPM): Higher random IOPS than NL-SAS at lower per-drive capacity. For workloads that need better random performance than NL-SAS without paying for full SSD.
• Mixed configurations: 2-4 SAS SSDs in select bays as a hot tier, 8-10 NL-SAS HDDs for capacity. OS or application-managed tiering. Improves effective throughput for frequently-accessed data without the cost of all-SSD.
• 3.5" SAS SSDs: A niche option. Significantly more expensive per TB than 2.5" SAS SSDs in 3.5" sleds. Rarely the right call; consider the 16-Bay 2.5" SFF chassis for SSD workloads instead.

BOSS-S2 module standard for OS boot. All 12 LFF front bays remain available for data. Optional 2 x 2.5" rear drive kit available for additional flash tier or dedicated swap/log, with the associated reduction in rear PCIe slot count.

Storage Controllers

• PERC H755 (8 GB flash-backed cache): The production choice for capacity arrays. Flash-backed write cache means no battery replacement cycle. RAID 0/1/5/6/10/50/60; RAID 6 is the standard configuration for large NL-SAS arrays on this chassis.
• PERC H745 (4 GB flash-backed cache): Mid-tier alternative for smaller arrays or where the H755's larger cache is not justified. Still supports RAID 6.
• PERC H355/H345: Entry-tier RAID, RAID 0/1/10 only; these controllers do not do RAID 5/6. Because RAID 6 is mandatory on the large NL-SAS drives this chassis is built for, the H755 or H745 is the correct controller for capacity arrays; the H355/H345 is only appropriate for small mirrored sets.
• HBA355i (pass-through): For Ceph, ZFS, GlusterFS, and any software-defined storage stack that manages its own redundancy. Presents drives directly to the OS with no RAID controller in the data path.
• S150 software RAID: Chipset-level software RAID for very entry-tier configurations only. Not a recommendation for production capacity arrays.

Networking

One OCP 3.0 mezzanine slot plus the PCIe Gen4 expansion slots for add-in NICs. Spinning-disk capacity arrays rarely saturate high-speed links on random workloads, but large sequential NAS and backup streams, and Ceph recovery and rebalance traffic, do benefit from bandwidth headroom.

• Dual-port 25 GbE SFP28 (OCP 3.0): The standard recommendation for NAS, file serving, and most capacity workloads on this chassis.
• Dual-port 100 GbE QSFP28: For Ceph cluster/backend networks and high-throughput backup ingest where recovery and rebalance traffic would otherwise bottleneck on 25 GbE.
• Quad-port 10 GbE SFP+ or quad-port 1 GbE RJ45: Network segmentation, dedicated management VLANs, and lower-bandwidth deployments.

Power Supplies

The 12-Bay LFF configuration draws less peak power than the GPU-heavy 16-Bay or 24-Bay configurations: no GPU power budget and modest CPU TDP for typical storage workloads. PSU sizing tracks the workload:

Physical Specs & Platform Notes

• Form factor: 2U rack, standard 19" rack-mount.
• Chassis depth: 28.17 inches (715.5 mm). Verify rack depth supports this; some short-depth racks will not.
• PCIe expansion: Up to 8 PCIe Gen4 slots depending on riser configuration; the optional 2 x 2.5" rear drive kit trades rear slot count for a small flash tier.
• Parts availability: Strong. The R750 is current-production at Dell with active ProSupport; PERC H755/H745, HBA355i, BOSS-S2, OCP 3.0 NICs, PSUs, and rails are all readily sourced.
• Platform notes: SAS/SATA LFF backplane only (no NVMe path); no GPU support on this chassis; RAID 6 mandatory on 14 TB+ NL-SAS.

Workload Patterns

NAS file servers: The largest single use case. 12 x 18-20 TB NL-SAS at RAID 6 delivers approximately 160-180 TB usable for SMB / NFS / iSCSI exports. PERC H755 handles RAID; 256-512 GB memory for file system cache; 25 GbE networking standard. The platform handles dedup and compression overhead well with Gold-tier CPUs.

Backup-to-disk targets: Veeam, Commvault, Veritas, and similar backup platforms benefit from the high sequential write throughput of 12-drive NL-SAS arrays. RAID 6 mandatory. Dedupe-aware backup software benefits from Gold-tier compute and 512 GB+ memory.

Ceph capacity-tier OSD nodes: 12 OSDs per node at 18-20 TB each = 216-240 TB raw per node. Bluestore on HBA355i pass-through. Memory budget: 4-8 GB per OSD plus headroom = 96-128 GB minimum, 192 GB for well-provisioned nodes. The R750's 32 DIMM slots provide architectural headroom Ceph deployments often want.

Archive and cold-tier storage: Long-term retention, compliance archives, video/imagery archives. RAID 6, conservative configuration, minimum-required CPU and memory. Cost-per-TB is the primary design metric.

Converged storage + compute: When the storage node also runs meaningful application compute (Ceph plus client workloads, NAS plus database, backup plus dedup engine), the R750's full dual-socket Ice Lake is the differentiator vs. value-tier 2U LFF storage platforms.

When to Pick a Different Chassis

• Need NVMe / vSAN ESA? → R750 24-Bay 2.5" (NVMe-capable backplane).
• Need SFF SSD storage? → R750 16-Bay 2.5" (canonical).
• Need GPU compute? → R750 16-Bay 2.5" (12-Bay LFF does not support GPUs).
• Single-socket-optimized economics? → R750xs 12-Bay 3.5" (same LFF capacity, single-socket pricing).
• 14th gen cost-primary procurement? → R740xd 12-Bay 3.5" (Cascade Lake, lower cost, equivalent storage performance).
• Smaller LFF capacity (8 bays)? → R540 12-Bay or R550 8-Bay 3.5".

Our Assessment

The R750 12-Bay 3.5" is the right call when you need LFF capacity at 15th gen platform currency with dual-socket compute alongside. NAS deployments with substantial dedup/compression overhead, Ceph capacity OSD nodes with converged client workloads, and backup targets with platform lifecycle through late 2020s are the canonical use cases.

Where it falls short of the right answer: pure cost-optimized bulk storage with 2-3 year lifecycle plans where 15th gen platform currency does not earn its premium. The R740xd 12-Bay delivers equivalent storage performance at meaningfully lower acquisition cost. We will quote both and let the lifecycle math drive the decision.

Bottom line: for capacity storage that will run through the late 2020s with active vendor support and converged compute requirements, the R750 12-Bay is the platform. For 14th gen-class storage at lower cost, the R740xd is the platform.

Workload Fit

Honest Limitations

• No NVMe path on the front bays. The 12-Bay 3.5" backplane is SAS/SATA only. For NVMe, the 24-Bay 2.5" is the R750 chassis.
• No GPU support, period. Per Dell's service manual, the 12-Bay 3.5" chassis explicitly excludes GPU configurations. Do not procure this chassis with any GPU intent.
• Long RAID rebuild times on large drives. 18-20 TB NL-SAS at full rebuild can exceed 24 hours. RAID 6 is mandatory at this drive size. Hot spare strongly recommended.
• Spinning-disk performance ceiling. 12 NL-SAS HDDs at 15K spindle speed deliver substantial sequential throughput but limited random IOPS, typically 200-300 random IOPS aggregate. Workloads needing random IOPS at scale belong on SFF SSD chassis.
• 3.5" SAS SSD is rarely the right call. Per-TB cost is significantly higher than equivalent 2.5" SAS SSD. If SSD is the requirement, the 16-Bay 2.5" chassis is the right platform.
• Spinning-disk acoustic profile is louder than all-flash. 12 active HDDs in a 2U chassis generate meaningful vibration and noise. Data center placement only.
• Drive weight matters at full population. 12 x 20 TB NL-SAS drives add roughly 24 lbs of rotating media to the chassis. Full-loaded R750 12-Bay exceeds 75 lbs. Two-person lift mandatory.

Generation Context

vs. R740xd 12-Bay (14th gen Cascade Lake predecessor): Same chassis form factor and LFF storage capacity. The R750 12-Bay adds PCIe Gen4 (vs. Gen3), Ice Lake processors (better per-core performance, lower idle power), 32 DIMM slots (vs. 24 on R740xd), Universal Backplane architecture, and active Dell ProSupport (R740xd is out of mainstream support). For storage workloads where drive performance is the bottleneck, the practical performance delta is modest; the drives limit throughput, not the CPU generation. The R750 12-Bay earns its premium over the R740xd when ProSupport, Ice Lake compute on converged workloads, or platform lifecycle alignment matter.

vs. R760 (16th gen Sapphire Rapids successor): R760 brings DDR5 and PCIe Gen5, neither of which meaningfully changes spinning-disk storage performance. For pure capacity workloads, the R750 12-Bay at refurbished pricing is the cost-correct call. R760 makes sense when the storage node also runs significant DDR5-bandwidth-sensitive compute.

vs. R750xs 12-Bay 3.5" (single-socket-optimized companion): Same LFF capacity and chassis form factor, but the R750xs 12-Bay 3.5" is single-socket-optimized: 16 DIMM slots (vs. 32), lower PSU envelope, no Optane PMem, lower acquisition cost. For pure storage nodes where dual-socket compute is not needed, R750xs is the cost-correct call. For converged storage + meaningful compute, R750 is the platform.

vs. R750 16-Bay 2.5" (canonical R750): Trade LFF capacity drives for SFF SSD/HBA flexibility. The R750 16-Bay 2.5" is the canonical R750 platform for general-purpose 2U workloads. The 12-Bay 3.5" is the capacity-storage specialization.

Ready to Configure?

Tell us your capacity target, workload type (NAS / backup / Ceph / archive), memory target, network speed requirement, and quantity. We respond within 24 hours and will quote both R750 12-Bay and R740xd 12-Bay for a generational cost comparison where relevant. Volume pricing applies at 5 units and above.

Every Wholesale Servers R750 ships after a 12+ hour burn-in test covering every drive bay, memory channel, and PCIe slot. Standard 180-day warranty included; 1-Year, 2-Year, and 3-Year Premium warranty options available. Call 1-800-778-1545 or use the quote form on this page.