- Statement of Changes in Beneficial Ownership (4)

FORM 4 [ X ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0287 Expires: February 28, 2011 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(f) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* SEQUOIA CAPITAL X	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)
(Last) (First) (Middle) C/O SEQUOIA CAPITAL, 3000 SAND HILL RD, BLDG 4-250	3. Date of Earliest Transaction (MM/DD/YYYY) 12/17/2010
(Street) MENLO PARK, CA 94025 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	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. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	12/17/2010	12/17/2010	U		11651603	D	$33.85	0	I	See footnote ⁽¹⁾

*Table II - Derivative Securities Beneficially Owned ( e.g.* , puts, calls, warrants, options, convertible securities)**
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)

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.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
SEQUOIA CAPITAL X C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 MENLO PARK, CA 94025		X
SC X MANAGEMENT LLC C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 MENLO PARK, CA 94025		X
SEQUOIA CAPITAL X PRINCIPALS FUND LLC C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 MENLO PARK, CA 94025		X
SEQUOIA TECHNOLOGY PARTNERS X LP C/O SEQUOIA CAPITAL 3000 SAND HILL RD, BLDG 4-250 MENLO PARK, CA 94025		X

Signatures
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
^** Signature of Reporting Person		Date
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
^** Signature of Reporting Person		Date
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
^** Signature of Reporting Person		Date
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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