SECOND AMENDMENT TO DIGITAL REALTY TRUST, INC., DIGITAL SERVICES, INC. AND

Exhibit 10.4

SECOND AMENDMENT TO

DIGITAL REALTY TRUST, INC., DIGITAL SERVICES, INC. AND

DIGITAL REALTY TRUST, L.P. 2004 INCENTIVE AWARD PLAN

THIS SECOND AMENDMENT TO DIGITAL REALTY TRUST, INC., DIGITAL SERVICES, INC. AND DIGITAL REALTY TRUST, L.P. 2004 INCENTIVE AWARD PLAN, made as of February 15, 2007 (this “Second Amendment”), is made and adopted by Digital Realty Trust, Inc., a Maryland corporation (the “Company”). Capitalized terms used but not otherwise defined herein shall have the respective meanings ascribed to them in the Plan (as defined below).

WHEREAS, the Company maintains the Digital Realty Trust, Inc., Digital Services, Inc. and Digital Realty Trust, L.P. 2004 Incentive Award Plan (as amended, the “Plan”);

WHEREAS, pursuant to Section 14.1 of the Plan, the Plan may be amended from time to time by the Company’s Board of Directors (the “Board”); and

WHEREAS, the Company desires to amend the Plan as set forth herein.

NOW, THEREFORE, BE IT RESOLVED, that the Plan be amended as follows:

1. The definition of “Fair Market Value” set forth in Section 2.19 of the Plan is hereby amended and restated in its entirety as follows:

“2.19 “Fair Market Value” means, as of any given date, (a) if Stock is traded on an exchange, the closing price of a share of Stock as reported in the Wall Street Journal (or such other source as the Company may deem reliable for such purposes) for such date, or if no sale occurred on such date, the first trading date immediately prior to such date during which a sale occurred; or (b) if Stock is not traded on an exchange but is quoted on a quotation system, the mean between the closing representative bid and asked prices for the Stock on such date, or if no sale occurred on such date, the first date immediately prior to such date on which sales prices or bid and asked prices, as applicable, are reported by such quotation system; or (c) if Stock is not publicly traded, the fair market value established by the Committee acting in good faith.”

“(a) In the event of any stock dividend, stock split, combination or exchange of shares, merger, consolidation, spin-off, recapitalization or other distribution (other than normal cash dividends) of Company assets to stockholders, or any other change affecting the shares of Stock or the share price of the Stock, the Committee shall make proportionate adjustments to any or all of the following in order to reflect such change: (i) the aggregate number and type of shares that may be issued under the Plan (including, but not limited to, adjustments of the limitations in Sections 3.1 and 3.3); (ii) the terms and conditions of any outstanding Awards (including, without limitation, any applicable Performance Goals or Performance Criteria with respect thereto); and (iii) the grant or

exercise price per share for any outstanding Awards under the Plan. Any adjustment affecting an Award intended as Qualified Performance-Based Compensation shall be made consistent with the requirements of Section 162(m) of the Code.”

“15.17 Section 409A. To the extent that the Committee determines that any Award granted under the Plan is subject to Section 409A of the Code, the Award Agreement evidencing such Award shall incorporate the terms and conditions required by Section 409A of the Code. To the extent applicable, the Plan and Award Agreements shall be interpreted in accordance with Section 409A of the Code and Department of Treasury regulations and other interpretive guidance issued thereunder, including without limitation any such regulations or other guidance that may be issued after the Effective Date. Notwithstanding any provision of the Plan to the contrary, in the event that following the Effective Date the Committee determines that any Award may be subject to Section 409A of the Code and related Department of Treasury guidance (including such Department of Treasury guidance as may be issued after the Effective Date), the Committee may adopt such amendments to the Plan and the applicable Award Agreement or adopt other policies and procedures (including amendments, policies and procedures with retroactive effect), or take any other actions, that the Committee determines are necessary or appropriate to (a) exempt the Award from Section 409A of the Code and/or preserve the intended tax treatment of the benefits provided with respect to the Award, or (b) comply with the requirements of Section 409A of the Code and related Department of Treasury guidance.”

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I hereby certify that the foregoing Second Amendment was duly adopted by the Board of Directors of Digital Realty Trust, Inc. on February 15, 2007.

Executed on this 15^th day of February, 2007.

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