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Details Title: SnapView Foundations Description: EMC SnapView Foundations Total Flash Cards: 17 Created: 01/29/2005 18:27:18	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term SnapView Definition Creates point-in-time views (SnapShot) and copies (Clones) of logical volumes. Allows multiple copies of data (parallel access). Runs on CLARiiON. Instantly available and R/W capable. Term SnapView Snapshots Definition Pointer based. Only require fraction of source disk space. Copy on First Write. 8 snaps possible with single source volume/ Snapshot. Snapshots of clones are suported. "Roll back" provides instant restore to source volume. Term SnapView Clones Definition Full volume copy. Requires equal disk space. Term 3 Components of Virtual LUN Definition 1) Source LUN 2) Pointer Memory Map 3) Save Area Term SnapView Production Host Definition May have only 1 view of a LUN active at any time. May be source LUN or one of 8 snapshots. No host may have Source LUN and Snapshot accessible to it at the same time. Term SnapView Backup (secondary) host Definition Host where backup processing occurs. Accesses snapshots. Must be same OS type as production host for filesystem access (unless raw data). Term Source LUN Definition LUN from which Snapshots will be made Term Snapshot Definition "Frozen in time" copy of Source LUN. Up to 8 R/W snapshots per source LUN. Accessible to secondary host, but not to primary host once SnapView session = started. Used when only write to 20 - 30% of data. Appears "off-line" until session is activated. Copy on First Write. Term Reserved LUN Pool Definition Private area used to hold original data from Source LUN when host writes to a chunk for first time (contain copy on first write). 1 LUN Pool per SP. All Snapshot Sessions owned by a SP use 1 LUN Pool. Each Source LUN with active session is allocated 1+ Reserved LUNs. Fraction of Source LUN size. Term Reserved LUN Definition should be same size as original. Term Downsides to SnapView SnapShot Definition 1) Not as fault tolerant as Clone 2) Contention bwtn source and LUN 3) More overhead in memory and CPU process to keep track of memory map Term Benefits of SnapView SnapShot Definition 1) Instantly have virtual LUN 2) Uses fraction of space Term Benefits of SnapView Clone Definition 1) Safe: used for mission Critical information 2) higher level of service than Snapshot Term SnapView Session Definition Can be started / stopped from SnapView Manager/CLI or from production host via "admsnap". Requires session name. Term SnapView Analyzer Definition tracks statistics Term Chunk Definition SnapView snapshot original saved data. Fixed size of 64 KB. Saved when modified for the first time. Saved once per snapshot. Term Deactivation of SnapView Session Definition Makes snapshot inaccessible to the Backup host. Keeps COFW process active. Does not flush host buffers.