Hello,
If you did not create the 'isos' directory, then your .iso file is now named isos and is a single file. You should be able to see this using the Data Store Browser. Note copying ISOs will pause as it copies the data. Write to VMFS from the SC have been throttled and are MUCH slower than you expect.
Best regards,
Edward L. Haletky
VMware Communities User Moderator
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Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education. As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization