From 75a0a4aa8a4b955f6868ef1dadb80159d527cfd8 Mon Sep 17 00:00:00 2001 From: doc-claw-bot Date: Wed, 7 Oct 2026 12:25:43 +0000 Subject: [PATCH] docs: fix outdated Region size in multi-AZ deployment doc --- multi-data-centers-in-one-city-deployment.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/multi-data-centers-in-one-city-deployment.md b/multi-data-centers-in-one-city-deployment.md index 5f67a00b6040f..d215d6162b8ed 100644 --- a/multi-data-centers-in-one-city-deployment.md +++ b/multi-data-centers-in-one-city-deployment.md @@ -104,7 +104,7 @@ The following example assumes that three AZs (AZ1, AZ2, and AZ3) are located in #### TiKV labels -TiKV is a Multi-Raft system where data is divided into Regions and the size of each Region is 96 MB by default. Three replicas of each Region form a Raft group. For a TiDB cluster of three replicas, because the number of Region replicas is independent of the TiKV instance numbers, three replicas of a Region are only scheduled to three TiKV instances. This means that even if the cluster is scaled out to have N TiKV instances, it is still a cluster of three replicas. +TiKV is a Multi-Raft system where data is divided into Regions and the size of each Region is 256 MiB by default. Three replicas of each Region form a Raft group. For a TiDB cluster of three replicas, because the number of Region replicas is independent of the TiKV instance numbers, three replicas of a Region are only scheduled to three TiKV instances. This means that even if the cluster is scaled out to have N TiKV instances, it is still a cluster of three replicas. Because a Raft group of three replicas tolerates only one replica failure, even if the cluster is scaled out to have N TiKV instances, this cluster still tolerates only one replica failure. Two failed TiKV instances might cause some Regions to lose replicas and the data in this cluster is no longer complete. SQL requests that access data from these Regions will fail. The probability of two simultaneous failures among N TiKV instances is much higher than the probability of two simultaneous failures among three TiKV instances. This means that the more TiKV instances the Multi-Raft system is scaled out to have, the less the availability of the system.