- Optane p5800x drives cause brief poor performance/latency spikes when used as cache disks in vSAN where Intel E810c Network cards are used (Intel(R) Ethernet Controller E810-C for QSFP)
- Cache disk operations over 100MS latency under load.
- When using disk query, latency is evident:
vsish -e get /vmkModules/vmknvme/controllers//stats' in ESXi80u2, refer to the following cmds to get the controller number
1. esxcfg-scsidevs -A
2. esxcli nvme controller list > /vmkModules/vmknvme/controllers/260/> get /vmkModules/vmknvme/controllers/260/stats
- VSAN 8.0 U2
- Issue does not occur using other network interfaces, only Intel E810c
- Using AMD servers
- The BIOS setting in the “Dynamic Link Width Management (DWLM)” function seems to introduce the problem, with it set to “Forced” the extreme latency or “Receive Packet Dropped” dissipate.
- NVMe disk latency caused by combination of AMD BIOS settings and Intel E810c Ethernet Cards
Set BIOS settings on AMD chipset motherboard in accordance with third party documentation: Tuning Guide AMD EPYC 7003, section 2.1.2.