> For the complete documentation index, see [llms.txt](https://docs.parallels.com/landing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.parallels.com/landing/ras-admin-guide/v22-ja-jp/load-balancing-and-halb/high-availability-load-balancing-halb/prerequisites.md).

# 前提条件

以下に、HALB を使用するために必要な前提条件を強調表示します。

* HALB の前段に配置されたセキュリティエッジ ゲートウェイまたはルーターが、クライアント コンピューターの送信元 IP アドレスを維持するように構成されていること

### サイジングのレコメンデーション

<table data-header-hidden="false" data-header-sticky><thead><tr><th width="128">トラフィックプロファイル</th><th>同時TCPセッション数</th><th>おすすめ vCPU 数</th><th>おすすめRAM</th><th>Skype ノート/Skype メモ</th></tr></thead><tbody><tr><td><strong>負荷の低いペイロード</strong></td><td>最大 <strong>12,500</strong></td><td><strong>2 vCPU</strong></td><td><strong>2 GB</strong></td><td>ペイロードが小さく、送信頻度が低い場合に安全かつ安定</td></tr><tr><td><strong>中程度の負荷のペイロード</strong></td><td>最大12<strong>,500</strong></td><td><strong>4 vCPU</strong></td><td><strong>2～4 GB</strong></td><td>持続的な負荷下でもヘッドルームがあり、CPU効率が向上</td></tr><tr><td><strong>中程度のペイロード</strong></td><td>最大20<strong>,000</strong></td><td><strong>8 vCPU</strong></td><td><strong>4 GB</strong></td><td>高いコンカレンシーにおいてCPUの飽和を回避するために要件</td></tr><tr><td><strong>すべてのプロファイル</strong>（一般的なガイダンス）</td><td>任意</td><td>—</td><td><strong>4 GB（推奨）</strong></td><td>4 GBのRAMがあれば、長時間にわたる高負荷動作時にも、さらなる安全マージンと回復性が確保されます</td></tr></tbody></table>


---

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