Guild Wars 2

Should I go full zerk with my s/d LH ele or to mix zerk ad a little bit of soldier for survivability?

I guess you are talking about PvE.
S/D + LH is indeed best played with zerker scholar
How much more survivability you need is dependent on your team and your skill level.
You can find survivability in traits and gear. If you decide to switch pieces from zerker to soldier then you should do it in this descending order of priority: legs/head, chest, weapons, rest.