NEC S2900 User Manual

Contents

NEC S2900 User Manual Manual pdf 122 page image

10513.Snap ShotThe snap shot function can instantaneously make a virtual copy of a logical disk in the same disk arrayunit. Only the difference data between the copy source and the virtual copy is managed, so copies canbe of a small size.The following specific software (available optionally) is necessary for using the Snap Fhot feature.NEC Storage S2500/S1500 contains the Dynamic Data Replication and Snap Shot as paired package.For details on the usage, refer to the User's Guide provided with the software.Before the feature can be used on this disk array unit, the license lock must be released by using thelicense key provided with the software.You can release the license lock and make setting changes by yourself.An NEC maintenance service representative may provide the installation service (at an additionalcharge) for releasing the license lock and changing settings. Contact your maintenance servicerepresentative if necessary.13.1 Note on Using Snap ShotSnapShot manages the difference data between the logical disk as the copy source and the virtual copy,as a map in the cache memory. Thus, if the disk array unit is turned OFF and the time limit for holdingdata by batteries is exceeded, processing for creating the management information of the differencedata is performed upon the next system start. As a result, the system startup is delayed depending onthe difference data held by Snap Shot. (Delay time: About 10 minutes per 1TB of difference data )So, to avoid the huge delay at next system startup with fully a discharged battery, please begin theshutdown process by pushing the Shutdown button before the power to the disk array unit is turnedOFF. As the management information of the difference data will be stored on hard disk by properexecution of shutdown process, the delay of the next system startup with fully discharged battery willbe reduced considerably.