JBOD Span after one disk failure

I have  WD ShareSpace with 4x1TB HDD

I want to ask what will happen after one of disk dead in JBOD Span array, will i lose everythinh like in RAID 0 and if i will not lose only dead hdd information , can i just replace hdd and continue to use array with lose of only informaiton from dead hdd.

Just as with RAID 0 you will lose access to all of your data if one or more drives fail.  Stick with RAID 5 and remember that RAID is not backup.  Keep a copy of your important data somewhere else in addition to having it on your ShareSpace.