X0202 3 2008-03-11 0 0001373671 Isilon Systems, Inc. ISLN 0001186035 HELSEL BRETT 3101 WESTERN AVENUE SEATTLE WA 98121 false true false false SVP Engineering Common Stock 700 D Stock Option (Right to Buy) 5.18 2017-12-17 Common Stock 2000 I By Spouse Stock Option (Right to Buy) 9 2017-08-16 Common Stock 3000 I By Spouse The option is exercisable at the rate of 1/4th of the shares on December 10, 2008 and 1/12th of the remaining shares on each quarterly anniversary thereafter, such that the option will be fully exercisable on December 10, 2011. The option is exercisable at the rate of 1/4th of the shares on July 31, 2008 and 1/12th of the remaining shares on each quarterly anniversary thereafter, such that the option will be fully exercisable on July 31, 2011. Keenan M. Conder, Attorney-in-Fact 2008-03-19