摘要:
A system and method for detecting a failure of a first process is disclosed. According to one aspect, a first connection is established between a first process and a second process. A monitoring mechanism monitors the status of the first process to detect whether the first process has failed. In response to determining that the first process has failed, the monitoring mechanism causes an out-of-band message to be sent to the second process.
摘要:
A method and apparatus is provided for maintaining data integrity. According to the method, a physical checksum calculation is performed on a block of data. After performing the physical checksum calculation, a logical check is performed on the data contained with the block of data. If the block of data passes the logical check, then the block of data may be written to nonvolatile memory. Thereafter, when the block of data is read from nonvolatile memory a physical checksum verification procedure is performed on the block of data to determine whether the block of data was corrupted after performing the logical check on the data contained with the block of data.
摘要:
A method and corresponding apparatus for authenticating a client for a server when the client and server have different security mechanisms. An intermediary system known as an authentication gateway provides for authentication of the client using the client security mechanism, and impersonation of the client in a call to a server that the client wishes to access. The client logs in to the authentication gateway and provides a user name and password. Then the authentication gateway obtains and saves security credentials for the client, returning an access key to the client. When the client wishes to call the server, the client calls the authentication gateway acting as a proxy server, and passes the access key, which is then used to retrieve the security credentials and to impersonate the client in a call to the server. Any output arguments resulting from the call to the server are returned to the client through the authentication gateway.
摘要:
A storage device uses non-volatile memory devices for caching. The storage device operates in a mode referred to herein as write-back mode. In write-back mode, a storage device responds to a request to write data by persistently writing the data to a cache in a non-volatile memory device and acknowledges to the requestor that the data is written persistently in the storage device. The acknowledgement is sent without necessarily having written the data that was requested to be written to primary storage. Instead, the data is written to primary storage later.
摘要:
A method and apparatus for reducing down time in updating applications with metadata is provided. The application contains both code and metadata. A copy of the application is made. A software update is installed on the copy of the application. During installation, the original application continues to run and service users, who may modify the metadata of the original application. Periodically, the metadata of the copy of the application is updated to incorporate changes to the metadata of the original application. When the software update is completed, users are prevented from further modifying the metadata of the original application. The metadata of the copy of the application is updated to incorporate the final changes to the metadata of the original application. Users are redirected from the original application to the copy of the application.
摘要:
Techniques are described herein for returning a repository to a prior state. The repository may be, for example a database, and the prior state may be, for example the consistent state that the database had at a particular point in time in the past. When a operator-caused error has been introduced to the database by changes made by an already-committed transaction, the techniques described herein may be used to recover from the error by returning the database to a point in time prior to the commit time of the transaction that introduced the error. The techniques involve the generation of “physical undo” information, and the use of the physical undo information in conjunction with physiological undo and physiological redo to efficiently return a repository to the prior state.
摘要:
A method and apparatus is provided for maintaining data integrity. According to the method, a physical checksum calculation is performed on a block of data. After performing the physical checksum calculation, a logical check is performed on the data contained with the block of data. If the block of data passes the logical check, then the block of data may be written to nonvolatile memory. Thereafter, when the block of data is read from nonvolatile memory a physical checksum verification procedure is performed on the block of data to determine whether the block of data was corrupted after performing the logical check on the data contained with the block of data.
摘要:
A method and apparatus is provided for maintaining data integrity. According to the method, a physical checksum calculation is performed on a block of data. After performing the physical checksum calculation, a logical check is performed on the data contained with the block of data. If the block of data passes the logical check, then the block of data may be written to nonvolatile memory. Thereafter, when the block of data is read from nonvolatile memory a physical checksum verification procedure is performed on the block of data to determine whether the block of data was corrupted after performing the logical check on the data contained with the block of data.