SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* SEQUOIA CAPITAL X (Last) (First) (Middle) C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Isilon Systems, Inc. [ ISLN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 12/17/2010
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	12/17/2010	12/17/2010	U		11,651,603	D	$33.85	0	I	See footnote(1)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* SEQUOIA CAPITAL X (Last) (First) (Middle) C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* SC X MANAGEMENT LLC (Last) (First) (Middle) C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* SEQUOIA CAPITAL X PRINCIPALS FUND LLC (Last) (First) (Middle) C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* SEQUOIA TECHNOLOGY PARTNERS X LP (Last) (First) (Middle) C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Represents 9,291,352 shares held by Sequoia Capital X, 999,345 shares held by Sequoia Capital X Principals Fund and 1,360,906 shares held by Sequoia Technology Partners X. SC X Management, LLC is the sole general partner of Sequoia Capital X and Sequoia Technology Partners X LP, and the managing member of Sequoia Capital X Principals Fund. As a result, SC X Management LLC may be deemed to share voting and dispositive power with respect to the shares of Common Stock held by Sequoia Capital X, Sequoia Technology Partners X LP and Sequoia Capital X Principals Fund. SC X Management LLC disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

	By Sequoia Capital X, By SC X Management, LLC, its General Partner By Douglas M Leone, its Managing Member, By Melinda Dunn as attorney-in-fact	12/21/2010
	By Sequoia Capital X Principals Fund LLC, By SC X Management, LLC, its General Partner By Douglas M Leone, its Managing Member, By Melinda Dunn as attorney-in-fact	12/21/2010
	By Sequoia Technology Partners X LP, By SC X Management, LLC, its General Partner By Douglas M Leone, its Managing Member, By Melinda Dunn as attorney-in-fact	12/21/2010
	By SC X Management, LLC, By Douglas M Leone, its Managing Member, By Melinda Dunn as attorney-in-fact	12/21/2010
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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