SAS drives are enterprise-grade with higher reliability and performance. Key differences: Speed: SAS supports up to 12 Gb/s vs SATA's 6 Gb/s. Dual-port: SAS drives have two ports for failover; SATA has one. Full-duplex: SAS can read and write simultaneously; SATA is half-duplex. Error handling: SAS has better SCSI command set for enterprise features. RPM options: SAS offers 10K and 15K RPM; SATA maxes at 7200. SAS drives cost more but are built for 24/7 mission-critical use.

No, SAS drives require a SAS controller or HBA (Host Bus Adapter). The connectors look similar but are not compatible. However, SATA drives CAN work with SAS controllers — SAS is backward compatible with SATA. For homelab use, you can get used SAS HBAs (like LSI 9211-8i) for $20-50 that work great. Many server motherboards include onboard SAS controllers. If you're building new, verify your hardware supports SAS before buying SAS drives.

It depends. Advantages: enterprise reliability, great value on refurbished drives, 10K/15K RPM options for speed. Disadvantages: requires SAS controller, louder than consumer drives, higher power consumption. For homelab enthusiasts: refurbished SAS drives offer amazing $/TB value. For typical home NAS: SATA drives (IronWolf, Red Plus) are simpler and quieter. If you already have a server with SAS, definitely use SAS drives. If building new, SATA is usually more practical unless you specifically need SAS features.

RPM (rotations per minute) indicates spindle speed. 15K RPM: Fastest, lowest latency (~2ms), best for random I/O and transactions, typically smaller capacity (300GB-900GB). 10K RPM: Good balance, moderate latency (~3ms), larger capacities available (up to 2.4TB). 7.2K RPM (Nearline): Same as SATA speed (~4.2ms), highest capacity (up to 18TB+), best $/TB. For databases and VMs, 10K/15K reduces latency. For bulk storage, 7.2K nearline SAS offers capacity with SAS reliability.

Generally yes, with caveats. Enterprise drives are built for 5+ years of 24/7 use — many refurbished drives have plenty of life left. Check SMART data (power-on hours, reallocated sectors) before heavy use. Buy from reputable sellers with warranties (30-90 days typical). Enterprise drives have higher rated workloads (550TB/year) than consumer drives. For critical data: use RAID and backups regardless. For homelab/testing: refurbished SAS is excellent value. Avoid drives with high reallocated sector counts or errors.

NVMe is faster; SAS is mature and proven. NVMe SSDs: Higher throughput and IOPS, lower latency, newer technology, uses PCIe lanes. SAS SSDs: Proven enterprise reliability, works with existing SAS infrastructure, dual-port redundancy, mature ecosystem. For new builds: NVMe is increasingly preferred. For existing SAS infrastructure: SAS SSDs drop in without changes. For maximum reliability: SAS dual-port provides hardware-level redundancy. Both are excellent for enterprise; NVMe is the future but SAS remains standard in many data centers.

Popular homelab choices: LSI 9211-8i (8-port, IT mode for JBOD/ZFS, ~$25-40 used), LSI 9207-8i (newer version), Dell H310 (flashed to IT mode), or HP H220. These support SATA and SAS drives. For hardware RAID: LSI 9361-8i or similar. For ZFS/software RAID: use IT mode (passthrough) controllers. SAS3 (12 Gb/s) controllers are recommended for newer drives but SAS2 (6 Gb/s) works fine for HDDs. Get appropriate SAS cables (SFF-8087 to SFF-8482 for drives).

SAS drives are generally louder than consumer SATA drives. 15K RPM: Loudest, noticeable whine, not ideal for living spaces. 10K RPM: Moderate noise, audible but manageable. 7.2K Nearline: Similar to consumer drives, reasonable noise levels. Enterprise drives prioritize performance over acoustics — they're designed for data centers with dedicated cooling. For home office: consider 7.2K nearline or accept some noise. For quiet environments: SATA consumer drives or SSDs are better choices.