Test Case

Raspberry Pi AI document:

In case someone battling making NAS with large NVMEs... I'm almost 100% sure that 1A@5V(5.00W) is not enough for powering them. Example below is from 4x(Shenzhen Longsys Electronics Co., Ltd. Lexar NM790 NVME SSD (DRAM-less) (rev 01)).

smartctl -c /dev/nvme0

smartctl 7.4 2023-08-01 r5530 [aarch64-linux-6.11.0-1004-raspi] (local build) Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org
START OF INFORMATION SECTION

Firmware Updates (0x14): 2 Slots, no Reset required Optional Admin Commands (0x0017): Security Format Frmw_DL Self_Test Optional NVM Commands (0x005f): Comp Wr_Unc DS_Mngmt Wr_Zero Sav/Sel_Feat Timestmp Log Page Attributes (0x0e): Cmd_Eff_Lg Ext_Get_Lg Telmtry_Lg Maximum Data Transfer Size: 128 Pages Warning Comp. Temp. Threshold: 90 Celsius Critical Comp. Temp. Threshold: 95 Celsius

Supported Power States St Op Max Active Idle RL RT WL WT Ent_Lat Ex_Lat 0 + 6.50W - - 0 0 0 0 0 0 1 + 5.80W - - 1 1 1 1 0 0 2 + 3.60W - - 2 2 2 2 0 0 3 - 0.0500W - - 3 3 3 3 5000 10000 4 - 0.0025W - - 4 4 4 4 8000 41000

Supported LBA Sizes (NSID 0x1) Id Fmt Data Metadt Rel_Perf 0 + 512 0 0
After 2 days battling this is a partial workaroung I found working almost stable using RaidZ1(in RaidZ2 setup NAS still hangs after seconds when loaded).

With this command you are saying NVME drive to use power modes <=2.
 nvme set-feature /dev/nvme0 --feature-id=2 --value=2
You can check current power mode starus like this.
nvme get-feature /dev/nvme0 -f 2 get-feature:0x02 (Power Management), Current value:0x00000004
More info when available.

PSU I use is 20W that I use before so it's checked. I never saw under-voltage alarm on RPI5 itself. Same four drives connected on 4x4x4x4 bifurcatated PCIe3 slot on PC are performing like a beasts. Now I'm having stable configuration using both RaidZ1 and 2 by software limiting IO bursts to drives.