I thought it was an honorific, like if your party got a majority and you were a respected member, you got to carry the big fancy stick in to start the day and carry it out when it was over. I never thought there was any connection to actual weapons. Well, maybe way back in the day, but not in modern times.
Do you mean strictly Canadian or anyone with the title?
Sergant-At-Arms is a title that dates back many hundreds of years, and dates back to the direct armed retainers of the sitting Monarch in England. These were basically the King's personal guard, and often were also utilized for important government duties.
The tradition of a Sergeant-At-Arms in Parliamentary duty dates back to the 15th century. In early practice, their duties would have not just included security against outsiders, but security within the chamber itself; one has to remember that Parliament hasn't always been cordial, and the Sergeant-At-Arms would carry a weapon into parliament. Since MPs and Lords could not carry weapons (or armour) into the House of Commons or Lords by a 14th century law, one can see how he might be able to control the chamber.