繁忙時間にネットが止まった——POSはデータを失わず販売を続けられるか？

回線障害で店舗を停止し、販売を重複させ、決済を失い、在庫を壊す必要はありません。オフライン取引、ローカル保存、決済制限、番号、競合、復旧を解説します。

オフラインは事業継続機能

Offline mode is a full business continuity design covering products, prices, taxes, permissions, payments, receipts, storage, inventory, and later synchronization.

The system should clearly define which actions continue offline and which require central data.

実際の障害を考えます。Offline mode is a full business continuity design covering products, prices, taxes, permissions, payments, receipts, storage, inventory, and later synchronization. Local records should contain complete sale details, device, employee, branch, sequence, and synchronization status. Offline card payments require separate risk limits because later authorization can fail. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Idempotency is required so retrying synchronization does not create duplicate sales. Receipt, order, and transaction identifiers must remain unique across all devices. The system should clearly define which actions continue offline and which require central data. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Sensitive data should remain encrypted and role-based access should still apply without the server. Stores should deliberately test outages, restarts, reconnection, duplicates, inventory, receipts, and payment settlement. When connectivity returns, transactions should upload through a controlled queue with confirmation and retry handling. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

ローカル取引は耐久性のある暗号化保存が必要

Every offline transaction must be saved immediately to durable local storage that survives restart, logout, battery loss, or crash.

Local records should contain complete sale details, device, employee, branch, sequence, and synchronization status.

実際の障害を考えます。Local records should contain complete sale details, device, employee, branch, sequence, and synchronization status. Limits can depend on amount, card type, branch, device, customer risk, and outage duration. Every offline transaction must be saved immediately to durable local storage that survives restart, logout, battery loss, or crash. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Stores should deliberately test outages, restarts, reconnection, duplicates, inventory, receipts, and payment settlement. Conflicts can involve stock, prices, customers, refunds, and simultaneous online activity, and rules should be visible. Conflicts can involve stock, prices, customers, refunds, and simultaneous online activity, and rules should be visible. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

決済には別のオフラインリスク規則が必要

Sensitive data should remain encrypted and role-based access should still apply without the server.

Offline card payments require separate risk limits because later authorization can fail.

実際の障害を考えます。The system should clearly define which actions continue offline and which require central data. Idempotency is required so retrying synchronization does not create duplicate sales. Offline mode is a full business continuity design covering products, prices, taxes, permissions, payments, receipts, storage, inventory, and later synchronization. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Receipt, order, and transaction identifiers must remain unique across all devices. Every offline transaction must be saved immediately to durable local storage that survives restart, logout, battery loss, or crash. Limits can depend on amount, card type, branch, device, customer risk, and outage duration. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。When connectivity returns, transactions should upload through a controlled queue with confirmation and retry handling. Offline mode is a full business continuity design covering products, prices, taxes, permissions, payments, receipts, storage, inventory, and later synchronization. Idempotency is required so retrying synchronization does not create duplicate sales. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Local records should contain complete sale details, device, employee, branch, sequence, and synchronization status. Limits can depend on amount, card type, branch, device, customer risk, and outage duration. Every offline transaction must be saved immediately to durable local storage that survives restart, logout, battery loss, or crash. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

番号は一意に保つ

Limits can depend on amount, card type, branch, device, customer risk, and outage duration.

Receipt, order, and transaction identifiers must remain unique across all devices.

実際の障害を考えます。Sensitive data should remain encrypted and role-based access should still apply without the server. Stores should deliberately test outages, restarts, reconnection, duplicates, inventory, receipts, and payment settlement. When connectivity returns, transactions should upload through a controlled queue with confirmation and retry handling. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Offline mode is a full business continuity design covering products, prices, taxes, permissions, payments, receipts, storage, inventory, and later synchronization. Local records should contain complete sale details, device, employee, branch, sequence, and synchronization status. Offline card payments require separate risk limits because later authorization can fail. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

同期競合を透明に解決する

Idempotency is required so retrying synchronization does not create duplicate sales.

When connectivity returns, transactions should upload through a controlled queue with confirmation and retry handling.

実際の障害を考えます。Every offline transaction must be saved immediately to durable local storage that survives restart, logout, battery loss, or crash. The system should clearly define which actions continue offline and which require central data. Receipt, order, and transaction identifiers must remain unique across all devices. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Limits can depend on amount, card type, branch, device, customer risk, and outage duration. When connectivity returns, transactions should upload through a controlled queue with confirmation and retry handling. Stores should deliberately test outages, restarts, reconnection, duplicates, inventory, receipts, and payment settlement. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Conflicts can involve stock, prices, customers, refunds, and simultaneous online activity, and rules should be visible. Offline card payments require separate risk limits because later authorization can fail. Local records should contain complete sale details, device, employee, branch, sequence, and synchronization status. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。Every offline transaction must be saved immediately to durable local storage that survives restart, logout, battery loss, or crash. The system should clearly define which actions continue offline and which require central data. Receipt, order, and transaction identifiers must remain unique across all devices. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

次の障害前に復旧を試験する

Conflicts can involve stock, prices, customers, refunds, and simultaneous online activity, and rules should be visible.

Stores should deliberately test outages, restarts, reconnection, duplicates, inventory, receipts, and payment settlement.

実際の障害を考えます。Offline card payments require separate risk limits because later authorization can fail. Sensitive data should remain encrypted and role-based access should still apply without the server. Sensitive data should remain encrypted and role-based access should still apply without the server. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。

実際の障害を考えます。The system should clearly define which actions continue offline and which require central data. Idempotency is required so retrying synchronization does not create duplicate sales. Offline mode is a full business continuity design covering products, prices, taxes, permissions, payments, receipts, storage, inventory, and later synchronization. 現金、オフラインカード、端末再起動、二端末で同じ少量在庫販売、価格変更、重複再送、アップロード前返品をテストします。