Continuous Access XP Journal vs. Continuous Access XP Extension
{"Image DocumentName": "Continuous Access XP Journal vs. Continuous Access XP Extension", "Image ImageDescription": "Remote. Copy. Primary Primary. 1. Remote. JNL. HP StorageWorks Continuous Access XP Journal can be compared and contrasted with traditional Continuous Access XP Extension (asynchronous) operation: CA XP Journal architecture is uniquely suited for one-to-many or one-to-one-to-one configurations. CA XP Async can only facilitate one-to-one configurations. With CA XP Journal, update data (in the form of the journal) is stored on traditional disk, while CA XP Async queues change data in array cache. This means that CA XP MS can be more tolerant of high or fluctuating workload environments where tracking/recording or update data can \u2018fall behind\u2019 primary data operations. Much more capacity in the form of disk can be provisioned to store such data with CA XP Journal and, thus, forms a more resilient \u2018buffer\u2019 for remote copy operations. With CA XP Journal, the journaled data consists of track-level change information. When the remote site journal \u2018reads\u2019 changes on the primary site journal, multiple track-level changes can be aggregated and retrieved . With CA XP Extension (Async) , transaction must be replicated across the remote link on an I/O by I/O basis. Depending on the application/database environment, such an \u2018atomic\u2019-level replication scheme can be very inefficient. Data. 3. cache. cache Data. Copy. JNL. Remote. 2nd. Copy JNL. CA XP Journal. CA XP Extension (using Sidefiles) Update data (Journal) is stored on Disk. Remote side initiates updates. Enables logical 1:2, 1:1:1 configurations. Strengths. Updates very efficient, less bandwidth required. Provides hi-capacity lower cost disk-based update data tracking. Best for\u2026 Multi-Site implementations. Update data (Sidefile) is stored in Cache. Primary side initiates updates. 1:1 configurations only. Strengths. Potential for better data currency. Best for\u2026 1:1 implementations.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}