Files
serverAppConfigs/docs/Dankserver System Specs.md
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Frank 9d7643ec5d frank-default-small: ncmoe 35->36 for prefill stability
Fix a live crash: cuBLAS cudaErrorInvalidValue in ggml_cuda_mul_mat_cublas
killed the service during a 145k-token prefill burst at ncmoe35/ub3072.

ncmoe 36 moves one more expert layer to CPU: frees ~0.75 GiB peak VRAM
(grid: peak 8606 vs 9360 MiB at ub3072) for -2% prefill / -2% decode.
Keeps prefill priority (top ubatch tier). Docs synced; noted fallback
GGML_CUDA_FORCE_MMQ=1 if pressure persists.
2026-08-14 10:56:40 -07:00

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# Dankserver System Specs
## Server Overview
Dankserver is an NVIDIA GPU server for vLLM inference. The host runs Ubuntu 24.04 with an RTX 3090 and 62 GB of system RAM.
## Hardware Specifications
### CPU
| Property | Value |
|----------|-------|
| Architecture | x86_64 |
| Vendor | AuthenticAMD |
| Model | AMD Ryzen 7 7700X |
| Cores | 8 (1 socket) |
| NUMA Nodes | 1 (node 0, 63503 MB) |
### GPU
| Property | Value |
|----------|-------|
| Model | NVIDIA GeForce RTX 3090 |
| VRAM | 24576 MiB (24 GB) |
| Driver | 595.84 |
| CUDA Version | 13.2 |
| CUDA Toolkit | 12.0 (nvcc) |
### Memory
| Property | Value |
|----------|-------|
| System RAM | 62 GiB |
| Swap | 127 GiB |
| /dev/shm | 32 GiB |
### Storage
| Filesystem | Size | Used | Avail | Use% |
|------------|------|------|-------|------|
| / (nvme0n1p2) | 915G | 729G | 140G | 84% |
| /mnt/entropy (dm-0) | 91T | 86T | 910G | 99% |
### OS and Software
| Property | Value |
|----------|-------|
| OS | Ubuntu 24.04.4 LTS (Noble Numbat) |
| Kernel | 7.0.0-28-generic |
| Python | 3.12.3 |
### Active Services
The active `frank-default-small` service (llama.cpp, `b10108+`) serves the HauhauCS Qwen3.6-35B-A3B uncensored `Q6_K_P` model on port 7770 with **ngram-mod** speculative decoding. It runs **4 parallel slots** at 200000 context each (pool 800000). Of the 40 layers' MoE expert weights, **36 sit on CPU** (`--n-cpu-moe 36`) while the remaining **4 layers' expert weights** are resident on GPU along with all non-expert tensors (`--gpu-layers all`). KV stays on GPU with K=`q8_0`, V=`f16`. Batch 8192 / ubatch 3072, `--ctx-checkpoints 4`, `--no-mmap`. At idle ~21.05 GB VRAM used, leaving an estimated **~3.0 GiB** headroom (chosen for prefill stability, see [[frank-default-small-benchmark]]). Idle RAM ~32 GB of 62 GB.
## Hardware Relevance
- 24 GB VRAM is close to saturated with this config. At idle ~21.05 GB used, leaving an estimated **~3.0 GiB** headroom at `--n-cpu-moe 36` (4 layers' experts on GPU) with `ubatch 3072`. A llama-bench sweep ([[frank-default-small-benchmark]]) guided this state: prefill is the priority, so `ubatch 3072` stays (top prefill tier), and `ncmoe 36` was raised from 35 to fix a cuBLAS OOM-class crash during big prefills by freeing ~0.75 GiB peak VRAM at only -2% prefill. If it still crashes under load, add `GGML_CUDA_FORCE_MMQ=1`. If decode speed matters more, use `ncmoe 32 - ubatch 1024` (gen ~48.7 t/s). By editing `scripts/frank-default-small.env`.
- 62 GB system RAM holds the ~29 GB of MoE expert weights with room to spare (~57 GB available after load).
- 127 GB swap is available for CPU KV cache paging if GPU KV offload is disabled.
- Root disk has approximately 140 GB free. Store the GGUF models under `/home/dank/models` (about 32 GB total).
## See Also
- [[VLLM Overview]]
- [[Hybrid CPU GPU Processing Dankserver]]
- [[RAM CPU Offloading in VLLM]]
- [[Running Qwen3.6 35B A3B FP8 on Dankserver]]