Hi, As far as I know, there is no number limitation of folders, but if you want to create folder tree, you will encounter path length. For more information, please refer to the following Microsoft TechNet and KB articles: Active Directory Maximum Limits - Scalability http://technet.microsoft.com/en-us/library/active-directory-maximum-limits-scalability(WS.10).aspx#BKMK_FileName Naming conventions in Active Directory for computers, domains, sites, and OUs http://support.microsoft.com/kb/909264 Regards, Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

We are using Windows 2008 (EC2) and have application that stores large number of subfolders in a specific folder (i.e. root/subfolder1, root/subfolder2, root/subfolder3 etc.) We are expecting tens of millions of subfolders and the question of scalability arised. Do you have any idea if Windows 2008 will be able to handle this? What about performance, is there a magic line after which any folder operations (e.g. creating new subfolder, or looking up exisiting) will drastically slow down? Are there any hard numbers? As an alternative we are considering converting that flat structure into a tree like root/subfolder1_/subfolder1, root/subfolder1_/subfolder11,...,root/subfolder2_/subfolder2,... etc) What is your opinion on that? Thanks, Piotr

To find an answer to your question, I just went through Windows Sysinternals 5's chapter - File Systems that I had. Found nothing about any limitations on the number of sub folders in a parent folder. Saw this - http://technet.microsoft.com/en-us/library/cc938937.aspx. Also, found nothing about any such limitation. Looked here - http://en.wikipedia.org/wiki/NTFS#Limitations, found nothing. So I don't think there any such limitation on number of subfolders. But I did find some information about optimizing NTFS for large number of files/folders - http://technet.microsoft.com/en-us/library/cc767961.aspx. As for your second query, it's mentioned in the same optimizing link above. Quoting from there: "Creating directory trees with dozens of levels and using enormous filenames detracts from the overall performance of your NTFS volumes. Although NTFS's performance is more tolerant of directory length and filename excesses than are other file systems, such as FAT, keep directories shallow and filenames short to maintain snappy performance. The system can navigate shallow directory structures more quickly and easily, and long filenames require additional storage space and processing overhead. I recommend that you keep NTFS directory trees to fewer than 10 levels deep, and filenames and directory names to fewer than 30 characters. These limits create an efficient directory structure that lets the volume maintain a higher level of performance." Please revert back here if you have any other questions. Hope it helps! Kunal D Mehta - a Windows Server Enthusiast.