What is Pasha?
It is my first name.

Is it a male or female name?
Male. (So, having deductive abilities, one may make conclusion about my gender).

Is it a real name or a nickname?
It is a pet-name formed from Pavel, which appears to be a rather typical Russian name. The Western equivalent is Paul. It has nothing to do with the Turkish title.

Why not Pavel or Paul?
Pavel? I just don't like it. (Let me repeat for occasional polite but not very quick-witted Russian correspondents, who automatically transform every name to the utmost full form as a sign of courtesy: please don't address me as Pavel).
I especially did not like since living in the Holy Land, for the reason that in Hebrew there are no hard "L", and with soft "L" it sounds particularly silly.
Paul? I should admit that I tried to use it during my first years in the Holy Land, but abandoned this idea as first, I am of Russian (or, rather, Soviet) and not of western origin, so it sounds a little bit unnatural and second, because of the same hard/soft "L" problem.
In addition to all that, I am unable to pronounce hard "L" correctly at all so the matters became a little bit complicated...

Why you spell it that way?
Because it seems to be a pretty damn standard English spelling of appropriate Russian word. Yeah, it's not at all how it should be spelled in Dutch, but Dutch people are known for their tolerance for obscure spelling, habits and gestures, so I was able to survive with it even in the Low Land. (Or, put it another way, the difficulty with my first name was overshadowed by the difficulty with my family name which typically perceived for the first time as a complex ritual greeting).
In Hebrew I used to write it like that:   ,   to be sure it will be read as "pasha" and not "pesha" or something else.
All at all, I managed (with moderate degree of success) to teach my dear Israeli and Dutch colleagues and friends to pronounce and spell it correctly.

How it is pronounced?
As is: pa-sha, accent on the first syllable. I especially like British pronunciation.

Is it the same as Sasha?
Absolutely not. It is also not the same as Yasha, Masha and Dasha, or whatever another Russian name you happen to be familiar with. (By the way, Masha is the name of my sister, and in childhood our mates called us together Pasha-Masha).