Exhibit 99.4

               John J. Stewart   Four Embarcadero Center   Suite 3200   San Francisco, CA 94111 VOTE BY INTERNET - www.proxyvote.com   Use the Internet to transmit your voting instructions by authorizing a proxy and for electronic delivery of information up until 11:59 P.M. Eastern Time the day before the meeting date. Have your proxy card in hand when you access the web site and follow the instructions to obtain your records and to create an electronic voting instruction form.   ELECTRONIC DELIVERY OF FUTURE PROXY MATERIALS   If you would like to reduce the costs incurred by our company in mailing proxy materials, you can consent to receiving all future proxy statements, proxy cards and annual reports electronically via e-mail or the Internet. To sign up for electronic delivery, please follow the instructions above to authorize a proxy using the Internet and, when prompted, indicate that you agree to receive or access proxy materials electronically in future years.   VOTE BY PHONE - 1-800-690-6903   Use any touch-tone telephone to transmit your voting instructions by authorizing a proxy up until 11:59 P.M. Eastern Time the day before the meeting date. Have your proxy card in hand when you call and then follow the instructions.   VOTE BY MAIL   Mark, sign and date your proxy card and return it in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717.

TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS:
	KEEP THIS PORTION FOR YOUR RECORDS
	DETACH AND RETURN THIS PORTION ONLY

THIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED.

The Board of Directors recommends you vote FOR proposals 1. and 2.:
						For	Against	Abstain
1. To approve the issuance of shares of Digital Realty Trust, Inc.’s common stock to the security holders of DuPont Fabros Technology, Inc. and DuPont Fabros Technology, L.P., pursuant to the Agreement and Plan of Merger, dated as of June 8, 2017, as may be amended from time to time, by and among Digital Realty Trust, Inc., Penguins REIT Sub, LLC, Digital Realty Trust, L.P., Penguins OP Sub 2, LLC, Penguins OP Sub, LLC, DuPont Fabros Technology, Inc. and DuPont Fabros Technology, L.P.						☐	☐	☐
2. To approve one or more adjournments of the special meeting to another date, time or place, if necessary or appropriate, to solicit additional proxies in favor of the proposal to approve the issuance of shares of Digital Realty Trust, Inc.’s common stock in connection with the mergers.						☐	☐	☐
NOTE: Such other business will be transacted at the meeting as may properly come before the meeting or any adjournments or postponements thereof.
For address change/comments, mark here.				☐
(see reverse for instructions)		Yes	No
Please indicate if you plan to attend this meeting		☐	☐
Please sign exactly as your name(s) appear(s) hereon and date. When signing as attorney, executor, administrator, trustee, guardian, officers of a corporation or other entity or in another representative capacity, please give full title as such under signature. Joint owners should each sign personally. All holders must sign.
Signature [PLEASE SIGN WITHIN BOX]	Date				Signature (Joint Owners)	Date

Important Notice Regarding the Availability of Proxy Materials for the Special Meeting:

The Notice & Proxy Statement is/are available at www.proxyvote.com

		DIGITAL REALTY TRUST, INC. Special Meeting of Stockholders September 13, 2017 10:30 AM PDT This proxy is solicited by the Board of Directors
	The undersigned, as record holder of the shares of common stock of Digital Realty Trust, Inc., a Maryland corporation, described on the reverse side, hereby appoints A. William Stein and Andrew P. Power, and each of them, as Proxies of the undersigned with the full power of substitution, to attend the Special Meeting of Stockholders to be held on Wednesday, September 13, 2017, at 10:30 a.m., local time, at Four Embarcadero Center, Suite 3200, San Francisco, California 94111, and any adjournment(s) or postponement(s) thereof, to cast on behalf of the undersigned all votes that the undersigned is entitled to cast at such meeting and otherwise to represent the undersigned at the meeting with all powers possessed by the undersigned if personally present at the meeting. The undersigned hereby acknowledges receipt of the Notice of the Special Meeting of Stockholders and of the accompanying Proxy Statement, the terms of each of which are hereby incorporated by reference, and revokes any proxy heretofore given with respect to such meeting. THE VOTES ENTITLED TO BE CAST BY THE UNDERSIGNED WILL BE CAST AS INSTRUCTED HEREIN. IF THIS PROXY IS EXECUTED BUT NO INSTRUCTION IS GIVEN, THE VOTES ENTITLED TO BE CAST BY THE UNDERSIGNED WILL BE CAST “FOR” EACH OF PROPOSALS 1 AND 2 AS DESCRIBED IN THE PROXY STATEMENT. THE VOTES ENTITLED TO BE CAST BY THE UNDERSIGNED WILL BE CAST IN THE DISCRETION OF THE PROXY HOLDER ON ANY OTHER MATTER THAT MAY PROPERLY COME BEFORE THE MEETING OR ANY ADJOURNMENT(S) OR POSTPONEMENT(S) THEREOF.             Address change/comments:
(If you noted any Address Changes and/or Comments above, please mark corresponding box on the reverse side.) Continued and to be signed on reverse side