2+sites = two or more active sites, 0/1 or more tie-breakers
Theoretically up to 64 sites are supported.
SANsymphony does not require a quorum or tie-breaker in stretched cluster configurations, but can be used as an optional component. The Virtual Disk Witness can provide a tie-breaker role if for instance redundant inter site paths are not implemented. The tie-breaker node (server or device) must be other than the two nodes presenting a virtual disk. Access to the Virtual Disk Witness is leading for storage node behavior.
There are 3 ways to configure the stretched cluster without any tie-breakers:
1. Default: in a split-brain scenario both sides stay active allowing upper infrastructure layers (OS/database/application) to make a decision (eg. clustering principles). In any case SANsymphony prevents a merge when there is a risk to data integrity, and the end-user has to make the choice on how to proceed next (which side is true)
2. Select one side to go inaccessible
3. Select both sides to go inaccessible.
DataCore, SSY [SDS]/10.0 PSP9, x86
SC Configuration, Disaster Recovery, Data Availability