diff --git a/content/operate/rs/clusters/optimize/disk-sizing-heavy-write-scenarios.md b/content/operate/rs/clusters/optimize/disk-sizing-heavy-write-scenarios.md index 14bd9a0ab9..77f1c8f531 100644 --- a/content/operate/rs/clusters/optimize/disk-sizing-heavy-write-scenarios.md +++ b/content/operate/rs/clusters/optimize/disk-sizing-heavy-write-scenarios.md @@ -10,31 +10,127 @@ description: Sizing considerations for persistent disk space for heavy throughpu linktitle: Disk sizing weight: $weight --- -In extreme write scenarios, when AOF is enabled, the AOF rewrite process -may require considerably more disk space for database persistence. - -To estimate the required persistent disk space in such cases, use the -formula described below. - -**The required persistent disk space for AOF rewrite purposes in extreme -write scenarios, assuming identical shard sizes:** - -**X (1 + 3Y +Y²)** -where: -**X** = each shard size -**Y** = number of shards - -Following are examples of database configurations and the persistence -disk space they would require in this scenario: - -| | Example 1 | Example 2 | Example 3 | Example 4 | -|---|------------|-----------------|------------|-----------------| -| Database size (GB) | 10 | 10 | 40 | 40 | -| Number of shards | 4 | 16 | 5 | 15 | -| Shard size (GB) | 2.5 | 0.625 | 8 | 2.67 | -| Required disk space (GB) | 73 | 191 | 328 | 723 | - -For disk size requirements in standard usage scenarios, refer to the -[Hardware -requirements]({{< relref "/operate/rs/installing-upgrading/install/plan-deployment/hardware-requirements.md" >}}) -section. +In extreme write scenarios when append-only files (AOF) are enabled, the AOF rewrite process can require considerably more disk space for [database persistence]({{}}). + +For disk size requirements for standard usage, see [Hardware requirements]({{< relref "/operate/rs/installing-upgrading/install/plan-deployment/hardware-requirements" >}}). + +## Estimate required disk space + +To estimate the required persistent disk space for AOF rewrite purposes in extreme write scenarios, use the following formula: + +**X (1 + 3Y + Y²)** + +Where: +- **X** = size of each shard in GB +- **Y** = number of shards + + +## Examples + +The following examples show how to calculate the persistent disk space required for heavy write scenarios for different database configurations, where: + +- **Database size** is the memory limit configured for the database. + +- **Number of shards** is the total number of shards (primary shards + replica shards). + +### Example 1 + +- Database size = 10 GB +- Number of shards = 4 + +1. Calculate the shard size: + + ```sh + Shard size = database size / number of shards + = 10 GB / 4 shards + = 2.5 GB per shard + ``` + +1. Use the formula to calculate the required persistent disk space: + + ```sh + Disk space = X (1 + 3Y + Y²) + = 2.5 (1 + 3 × 4 + 4²) + = 2.5 (1 + 12 + 16) + = 2.5 × 29 + = 72.5 GB + ``` + +1. Round up to 73 GB of required disk space. + +### Example 2 + +- Database size = 10 GB +- Number of shards = 16 + +1. Calculate the shard size: + + ```sh + Shard size = database size / number of shards + = 10 GB / 16 shards + = 0.625 GB per shard + ``` + +1. Use the formula to calculate the required persistent disk space: + + ```sh + Disk space = X (1 + 3Y + Y²) + = 0.625 (1 + 3 × 16 + 16²) + = 0.625 (1 + 48 + 256) + = 0.625 × 305 + = 190.625 GB + ``` + +1. Round up to 191 GB of required disk space. + +### Example 3 + +- Database size = 40 GB +- Number of shards = 5 + +1. Calculate the shard size: + + ```sh + Shard size = database size / number of shards + = 40 GB / 5 shards + = 8 GB per shard + ``` + +1. Use the formula to calculate the required persistent disk space: + + ```sh + Disk space = X (1 + 3Y + Y²) + = 8 (1 + 3 × 5 + 5²) + = 8 (1 + 15 + 25) + = 8 × 41 + = 328 GB + ``` + +1. Required disk space: 328 GB. + +### Example 4 + +- Database size = 40 GB +- Number of shards = 15 + +1. Calculate the shard size: + + ```sh + Shard size = database size / number of shards + = 40 GB / 15 shards + = 2.67 GB per shard + ``` + +1. Use the formula to calculate the required persistent disk space: + + ```sh + Disk space = X (1 + 3Y + Y²) + = 2.67 (1 + 3 × 15 + 15²) + = 2.67 (1 + 45 + 225) + = 2.67 × 271 + = 723.57 GB + ``` + +1. Round up to 724 GB of required disk space. + +