Solid State Drives (SSDs)

SAS vs SATA vs NVMe Server SSDs

NVMe SSDs connect directly via PCIe for the lowest latency and highest throughput. NVMe Gen 4 delivers up to 7 GB/s sequential read — 10x faster than SAS SSDs. Used for database storage, caching tiers, and latency-sensitive applications. Requires NVMe-capable drive bays or universal slots.

SAS SSDs provide dual-port connectivity for failover. They connect at 12 Gb/s, or at 22.5 Gb/s as 24G SAS when both the drive and the controller support it. Compatible with SAS-capable drive bays and SAS-capable Dell PERC and HPE Smart Array controllers.

SATA SSDs are the lowest-cost SSD option at 6 Gb/s. Single-port only. Suitable for boot drives, read-heavy workloads, and cost-sensitive deployments where SAS dual-port redundancy is not required.

Read-Intensive vs Mixed-Use vs Write-Intensive

Enterprise SSDs are rated by endurance class — the number of drive writes per day (DWPD) the drive is warranted for:

• Read-Intensive (RI) — Less than 1 DWPD. Lowest cost per GB. For read-heavy workloads: web serving, media streaming, boot drives, read replicas.
• Mixed-Use (MU) — 1-3 DWPD. Balanced read/write. For virtual machine datastores, general database, email servers.
• Write-Intensive (WI) — 3-10+ DWPD. Highest endurance. For write-heavy databases, OLTP, logging, caching tiers.

Choosing the right endurance class affects both cost and drive lifespan. Over-specifying wastes budget; under-specifying risks premature wear.

How to Choose the Right Server SSD

1. Check your server's interface support — NVMe requires NVMe-capable bays; SAS requires SAS-capable bays; SATA works in SAS or SATA bays
2. Match endurance to workload — RI for reads, MU for balanced, WI for writes
3. Select form factor — 2.5-inch (standard) or E3.S (16th Gen R660 only)
4. Contact Enterasource for volume pricing on multi-drive configurations

Frequently Asked Questions

What is the difference between read-intensive, mixed-use, and write-intensive SSDs?

Enterprise SSDs are rated by DWPD (drive writes per day) — the amount of write endurance warranted over the drive's service life. Read-intensive drives (under 1 DWPD) cost the least per gigabyte and are designed for workloads that are 90%+ reads, such as web serving, media delivery, and database read replicas. Mixed-use drives (1-3 DWPD) handle balanced read/write patterns for VM datastores and general databases. Write-intensive drives (3-10+ DWPD) withstand the heaviest write loads for OLTP, transaction logging, and caching tiers. Selecting the correct endurance class optimizes both cost and drive lifespan.

NVMe vs SAS SSD: which is better for my server?

NVMe SSDs connect directly to the PCIe bus and deliver up to 7 GB/s sequential read on Gen 4, with significantly lower latency than SAS. NVMe is the best choice for latency-sensitive databases, caching, and any workload that saturates SAS bandwidth. SAS SSDs provide dual-port redundancy and are managed by SAS-capable hardware RAID controllers (Dell PERC, HPE Smart Array). If your server has NVMe-capable bays and your workload benefits from maximum throughput, choose NVMe. If your server has SAS bays and a SAS-capable controller, choose SAS SSDs; SATA SSDs also work in SAS bays. For hardware RAID on NVMe, choose an NVMe RAID controller such as the Dell PERC H755N.

What SSD endurance class do I need for virtualization?

For most VMware vSphere and Hyper-V virtualization workloads, mixed-use (MU) SSDs rated at 1-3 DWPD are the standard. VM datastore I/O patterns are typically a 60/40 to 70/30 read/write mix, which aligns with mixed-use endurance. Read-intensive drives can work for lightly-written VM environments (VDI read replicas, web server pools), but risk premature wear under sustained VM provisioning or vMotion activity. Write-intensive drives are only necessary for dedicated database VMs with heavy transaction logging.

Need spinning storage for capacity workloads? Browse enterprise server hard drives. Looking for a complete storage build? Configure a server with pre-built RAID arrays.