In Crime & Punishment Rodya only has to serve 8 years for the double axe murder of two women in the commission of a robbery. It's a fictional tale about justice in 19th century Russia, but still an interesting comparison I think of when reading about modern sentencing.
Not in the imperial time, no. Dostoyevsky's The House of the Dead is an interesting account of his time in Siberia, and it wasn't all that bad.
It was different in Stalin's time, though. Varlam Shalamov's Kolyma tales tells a very different story. But even he survived after having served 15 years.
The mortality rate in the Kolyma gulags was estimated at 27%/year, meaning the odds of survival for 15 years were <1%, and virtually zero for general work (mining etc). Shalamov survived because he managed to land a position as a hospital attendant.
This assumes that random people die each year. However, if you survive for a year, you are probably very tough, and your life expectancy might actually go up.