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user80666
Asked: 2011-05-14 08:13:43 +0800 CST

How many folders is ok to have in a folder?

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On my website, users have files so I create a folder for each user when they register.

for example

/userdata/USERID

If site grows and I have thousands of users I might end up having too many user folders in one folder so i decided to split them up.

for example

/userdata/1/USERID (first thousand users)

/userdata/2/USERID (second thousand users)

My questions is how much folders should I put in one subfolder? Is 1000 in each a good idea? more? less? Just want to make sure things run smoothly.

linux apache-2.2

3 Answers

  1. Best Answer

    I always work to the rule of going for a maximum of ~1000 with ext2/ext3. I suspect that the choice of filesystem might affect your choice.

    The absolute limit in ext3 is ~32k. Have a look for all of the gory details on Wikipedia: http://en.wikipedia.org/wiki/Ext3

    In terms of a hashing algorithm for your directories I'd recommend using the last digit of the id. If you calculate $id % 10 and use that value it'll work a treat. That way you get an even distribution out of the box.

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  2. It depends mostly on the file system you are using.

    You'll probably find it easier to use a pattern rather then splitting on arbitrary numbers. CPAN, for instance, uses

    U/US/USERNAME

    i.e. first letter / first two letters / full username

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  3. If your usernames change infrequently, the CPAN mindset might still have an advantage. It's generally better to know for 90% of users where to drill down and find their content than to have to search N file structures looking for USERID.

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