Towards Resiliency in Large Language Model Serving with KevlarFlow

Fuente: arXiv
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Main Authors: Qian, Shangshu, Liu, Kipling, Sruthi, P. C., Tan, Lin, Zhang, Yongle
Format: Preprint
Published: 2026
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author Qian, Shangshu
Liu, Kipling
Sruthi, P. C.
Tan, Lin
Zhang, Yongle
author_facet Qian, Shangshu
Liu, Kipling
Sruthi, P. C.
Tan, Lin
Zhang, Yongle
contents Large Language Model (LLM) serving systems remain fundamentally fragile, where frequent hardware faults in hyperscale clusters trigger disproportionate service outages in the software stack. Current recovery mechanisms are prohibitively slow, often requiring up to 10 minutes to reinitialize resources and reload massive model weights. We introduce KevlarFlow, a fault tolerant serving architecture designed to bridge the gap between hardware unreliability and service availability. KevlarFlow leverages 1) decoupled model parallelism initialization, 2) dynamic traffic rerouting, and 3) background KV cache replication to maintain high throughput during partial failures. Our evaluation demonstrates that KevlarFlow reduces mean-time-to-recovery (MTTR) by 20x and, under failure conditions, improves average latency by 3.1x, 99th percentile (p99) latency by 2.8x, average time-to-first-token (TTFT) by 378.9x, and p99 TTFT by 574.6x with negligible runtime overhead in comparison to state-of-the-art LLM serving systems.
format Preprint
id arxiv_https___arxiv_org_abs_2601_22438
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Towards Resiliency in Large Language Model Serving with KevlarFlow
Qian, Shangshu
Liu, Kipling
Sruthi, P. C.
Tan, Lin
Zhang, Yongle
Distributed, Parallel, and Cluster Computing
Computation and Language
Machine Learning
Large Language Model (LLM) serving systems remain fundamentally fragile, where frequent hardware faults in hyperscale clusters trigger disproportionate service outages in the software stack. Current recovery mechanisms are prohibitively slow, often requiring up to 10 minutes to reinitialize resources and reload massive model weights. We introduce KevlarFlow, a fault tolerant serving architecture designed to bridge the gap between hardware unreliability and service availability. KevlarFlow leverages 1) decoupled model parallelism initialization, 2) dynamic traffic rerouting, and 3) background KV cache replication to maintain high throughput during partial failures. Our evaluation demonstrates that KevlarFlow reduces mean-time-to-recovery (MTTR) by 20x and, under failure conditions, improves average latency by 3.1x, 99th percentile (p99) latency by 2.8x, average time-to-first-token (TTFT) by 378.9x, and p99 TTFT by 574.6x with negligible runtime overhead in comparison to state-of-the-art LLM serving systems.
title Towards Resiliency in Large Language Model Serving with KevlarFlow
topic Distributed, Parallel, and Cluster Computing
Computation and Language
Machine Learning
url https://arxiv.org/abs/2601.22438