利用最新Hyper-V Replica 功能達成Hyper-V 災難備援機制 VIR301 利用最新Hyper-V Replica 功能達成Hyper-V 災難備援機制 講師姓名：張碩峯/何家霖 職稱：技術副理/技術專員 公司名稱：冠新資訊

TechReady 14 11/22/2018 每年平均停電時間 ? 1 3 6 25 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

每年平均停電時間? 每天停機成本 ? 1 3 6 25 $500 $3,850 $7,750 $12,500 TechReady 14 11/22/2018 每年平均停電時間? 1 3 6 25 每天停機成本 ? $500 $3,850 $7,750 $12,500 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

每年平均停電時間? 每天停機成本? 1 3 6 25 $500 $3,850 $7,750 $12,500 TechReady 14 11/22/2018 每年平均停電時間? 1 3 6 25 每天停機成本? $500 $3,850 $7,750 $12,500 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

每年平均停電時間? 每天停機成本? $500 1 3 6 25 $3,850 $7,750 $12,500 x 6 = $75,000! TechReady 14 11/22/2018 每年平均停電時間? 1 3 6 25 每天停機成本? $500 $3,850 $7,750 $12,500 x 6 = $75,000! © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

多少%的中小企業沒有災難復原計劃? 10 15 25 50 TechReady 14 11/22/2018 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

多少%的中小企業沒有災難復原計劃? 10 15 25 50! TechReady 14 11/22/2018 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

這 50% 中小企業災難復原計劃是….. TechReady 14 11/22/2018 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

會議的目的和重點 Hyper-V 複寫的關聯和概述 功能和價值的主張 部署的注意事項 TechReady 14 11/22/2018 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

關於Hyper-V 複製 Hyper-V & 容錯移轉叢集 Hyper-V 複本 資料中心內的高可用性 跨資料中心的可用性 Site A Site B

主要架構 台北總公司 高雄分公司 主要虛擬機 複本虛擬機 VHD VHD Log file (.hrl) Log file (.hrl) TechReady 14 11/22/2018 1:48 PM 主要架構 主要虛擬機 複本虛擬機 VHD Log file (.hrl) Log file (.hrl) VHD 台北總公司 高雄分公司 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

非同步複製 複本 主要 虛擬機 虛擬機 高雄分公司 台北總公司 Log File Log File TechReady 14 11/22/2018 1:48 PM 非同步複製 複本 虛擬機 主要 虛擬機 Log File Log File 台北總公司 高雄分公司 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Hyper-V 複本概述 整合在一起 災難復原情境 不需特定的 應用程式架構 不需特定 儲存架構 經濟實惠 易於管理 靈活

有彈性的部署 單機  單機 (網域 或 群組) 單機  叢集 叢集  單機 叢集  叢集 Tech Ready 15 11/22/2018 有彈性的部署 單機  單機 (網域 或 群組) 單機  叢集 叢集  單機 叢集  叢集 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

有彈性的部署 二個資料中心間的複寫 企業到託管資料中心間的複寫 託管的 資料中心 總公司 分公司 客戶 2 客戶 1 TechReady 14 11/22/2018 1:48 PM 有彈性的部署 託管的 資料中心 客戶 1 客戶 2 總公司 分公司 二個資料中心間的複寫 企業到託管資料中心間的複寫 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

無縫的虛擬機遷移 台北-1 台北-2 高雄-1 台北-3 高雄-2 高雄-3 台北總公司 高雄分公司

無縫的虛擬機遷移 台北-1 台北-2 高雄-1 台北-3 高雄-2 Hyper-V 複本 代理人 高雄-3 台北總公司 高雄分公司

增加新節點至叢集 台北-1 台北-2 高雄-1 台北-4 台北-3 高雄-2 高雄-3 台北總公司 高雄分公司 Allowed Primary Server Default storage location Trust Group MySeattle-1.contoso.com C:\Clus… Seattle MySeattle-2.contoso.com MySeattle-3.contoso.com 高雄-2 高雄-3 台北總公司 高雄分公司 Allowed Primary Server Default storage location Trust Group MySeattle-Broker.contoso.com C:\Clus… Seattle

11/22/2018 1:48 PM demo 複本設定 © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

彈性的複寫 故障後的彈性 虛擬機移動無縫操作 重試和恢復語法 重新同步 無需系統管理者介入需求 即時移轉、移轉存放裝置和快速移轉 TechReady 14 11/22/2018 1:48 PM 彈性的複寫 故障後的彈性 重試和恢復語法 重新同步 虛擬機移動無縫操作 無需系統管理者介入需求 即時移轉、移轉存放裝置和快速移轉 叢集內和跨叢集 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

虛擬機移動 台北 總公司 高雄 分公司 先決條件: 主要遷移: 所有伺服器必須得到授權 複本遷移: 需要Hyper-V 複本代理人

災難復原情境 災難復原 測試計劃 Site 維護 即將發生的災難 突發的災難

計劃性容錯移轉 主要伺服器步驟 複寫伺服器步驟 虛擬機關閉 啟動計劃的容錯移轉 傳送最後一次還原點 (複寫暫停變更) 合併最後一個還原點 Tech Ready 15 11/22/2018 計劃性容錯移轉 主要 虛擬機 主要伺服器步驟 虛擬機關閉 啟動計劃的容錯移轉 傳送最後一次還原點 (複寫暫停變更) 複寫伺服器步驟 合併最後一個還原點 反向複寫 開始虛擬機複寫 複本 虛擬機 台北總公司 高雄總公司 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

計劃性容錯移轉好處 災難復原測試、維護或是即將發生的災難 零資料遺失但會有停機時間 有效的反向複寫 持續的複寫 Site B Site A TechReady 14 11/22/2018 1:48 PM 計劃性容錯移轉好處 災難復原測試、維護或是即將發生的災難 零資料遺失但會有停機時間 有效的反向複寫 Site B Site A 持續的複寫 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

非計劃性容錯移轉 Site B複本伺服器選擇<容錯移轉> Site B選擇還原點 Site B移除複寫 待Site A修復 TechReady 14 11/22/2018 1:48 PM 非計劃性容錯移轉 Site B複本伺服器選擇<容錯移轉> Site B選擇還原點 Site B移除複寫 待Site A修復 重新啟用複寫至Site A Site B計劃性容錯移轉 主要Site A 複本Site B 正在進行複製 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

複本上的網路設定 複本的虛擬機網路連接 虛擬機識別碼在不同子網路 虛擬機名稱解析 複本 主要 10.22.100.XX Vswitch 建立和分配 VLAN 識別碼 虛擬機識別碼在不同子網路 添加靜態的 IP 位址 透過 DHCP自動分配 透過網路虛擬化保留 IP位址 虛擬機名稱解析 更新 DNS 記錄去對應新的IP 位址 15.25.10.XX 用戶端 Server IP Address SQLVM 15.25.10.XX Server Name IP Address SQLVM 10.22.100.XX

demo 計劃性容錯移轉 & 非計劃性容錯移轉 11/22/2018 1:48 PM 計劃性容錯移轉 & 非計劃性容錯移轉 © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

容錯移轉測試 工作階段中非中斷的測試 – 零停機 測試任何復原點 預先設定隔離的網路 Site A Site B TechReady 14 11/22/2018 1:48 PM 容錯移轉測試 工作階段中非中斷的測試 – 零停機 測試任何復原點 預先設定隔離的網路 Site A Site B © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11/22/2018 1:48 PM demo 測試容錯移轉 © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

容錯移轉測試展示環境 主要伺服器 複本伺服器 Win8連接到\\file-er\data-IT 讀取資料 正式環境 網路 測試環境 網路 TechReady 14 11/22/2018 1:48 PM 容錯移轉測試展示環境 正式環境 網路 測試環境 網路 主要伺服器 網域控制站 IP:192.168.2.80 檔案伺服器 IP:192.168.2.81 Win8 IP:192.168.2.82 網域控制站 複本 網域控制站-測試 IP:10.0.0.1 檔案伺服器 複本 檔案伺服器-測試 IP:10.0.0.2 Win8 複本 Win8-測試 IP:10.0.0.3 複本伺服器 Win8連接到\\file-er\data-IT 讀取資料 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

部署注意事項 中小企業 主機代管 企業 部署 客戶群 Hyper-V 複本 儲存 工作負載

用於複製的網路連接 要點 透過 VPN 透過 Internet 相互身份驗證 FQDN 為基礎的連接 DNS 解析 Primary VM Replica VM VPN Tailspin Toys Contoso.com 要點 相互身份驗證 FQDN 為基礎的連接 透過 VPN DNS 解析 維護複製同一份 DNS 區域 透過 Internet Public IPs 可使用NAT或不使用 Primary VM Replica VM Internet Tailspin Toys Contoso.com

網路頻寬 頻寬規劃是關鍵 估算資料的變動量 估算尖峰使用和有效的網路頻寬 1.5Mbps, 20ms latency, 1% packet loss

網路流量限制 使用 Windows Server 2012 QoS 去限制複寫的流量 以目的端子網路為限制基礎 以目的端埠為限制基礎 New-NetQosPolicy “Replication Traffic to 10.0.0.0/8” –DestinationAddress 10.0.0.0/8 –MinBandwidthWeightAction 40 以目的端埠為限制基礎 New-NetQosPolicy “Replication Traffic to 8080” –DestinationPort 8080 –ThrottleRateActionBytesPerSecond 10MB MinBandwidthWeightAction 參數，這個參數指定的最低頻寬，是指佔總頻寬的多 少百分比

網路使用率 同時複寫多台虛擬機器 透過排程進行網路傳送初始複本 管理增量複本複寫 太高的並發性會導致資源的爭用和延遲 太低的並發性會導致未充份利用 透過排程進行網路傳送初始複本 管理增量複本複寫 網路頻寬 並行傳輸理想數量 1.5 Mbps, 100ms, 1% packet loss 3 300 Mbps, 10ms, 1% packet loss 10

伺服器的影響 主要伺服器的影響 複本伺服器的影響 記憶體：每個複寫的 VHD約50MB CPU 的影響 <3% 儲存空間: 同比例虛擬機的寫入 儲存IOPS:約在1.5倍的寫入 IOPS 複本伺服器的影響 儲存空間: 與來源虛擬機同比例 每個額外的復回點 ~原VHD大小的10% 儲存IOPS: 0.6 倍的寫入 IOPS執行接收與轉換 3-5 倍的 IOPS 執行額外復原點的接收、 應用、合併 記憶體：每個複寫的 VHD約50MB CPU 的影響 <3%

demo 跨區域Hyper-V複本（VPN） 11/22/2018 1:48 PM © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

回顧：會議的目的和重點 Hyper-V 複寫與何時使用的相關性 功能和價值的主張 部署注意事項 使高可用性和遷移更加完整 內建的解決方案 TechReady 14 11/22/2018 回顧：會議的目的和重點 Hyper-V 複寫與何時使用的相關性 使高可用性和遷移更加完整 功能和價值的主張 內建的解決方案 靈活的部署情境 全面的複本和容錯移轉功能 部署注意事項 網路 系統的影響 © 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.