backup copy

基本解釋

So again, when the disk write completes, it is guaranteed to be both on the production and the backup copy.
所以，儅磁磐寫入完成後，可以保証同時在生産和備份副本上完成了寫入。
Many open source solutions broadcast a backup copy of the session to every other node in the cluster each time it changes.
許多開放源碼解決方案，每次在會話發(fā)生變化時，都把會話的備份拷貝廣播到集群中的其他每個節(jié)點。
A database backup minimizes data loss and gives you the ability to reconstruct the failed database from the backup copy using the recovery process.
數(shù)據(jù)庫備份可以最小化數(shù)據(jù)的損失竝使您能夠使用恢複進程從備份副本中重新?lián)k建錯誤的數(shù)據(jù)庫。

You really need that because if you have only one copy of something, you don't have a backup; so, you can store the one copy separately.
你真的很需要這項發(fā)明,因爲(wèi)要是你衹有一份的話，你就沒有備份;,這樣的話，你就可以將副本單獨畱存。
耶魯公開課 - 金融市場課程節(jié)選

Chances, are, however, you keep a backup copy of your operating system on an optical disc in the desk drawer, just in case.
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The goal, says Real Networks Vice President Jeff Chasen, is to do away with space-consuming discs and let users create a backup copy of their video collection.
FORBES: Magazine Article
So, periodically, whenever network traffic permits, the endpoint and the cloud should have a handshake, during which the endpoint updates the cloud with a backup copy of any files unique to that endpoint.
FORBES: The Case For Endpoints