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From: birre <spamt...@norsborg.net>
Newsgroups: alt.os.linux.suse
Subject: Re: Maximum amount of files per directory
Date: Tue, 06 Nov 2007 13:40:37 +0100
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On 2007-11-06 10:22, Merlin Morgenstern wrote:
> Andreas schrieb:
>> Hi,
>>
>> Merlin Morgenstern wrote:
>>> thank you for your reply. How can I find out which file system I am 
>>> running on the machine?
>>
>> The mount command or the /etc/fstab file.
>>  
>>>> Lookups should be in some O(log n).
>>> I am sorry, what does that mean? Can you be more specific?
>>
>> It means that the time would increase, but not linear. Having ten times
>> as many files won't take ten times longer.
>>
>> kindr regards,
>> Andreas
> 
> HI Anreas,
> 
> the filesystem is:
> /dev/sda7 on /home type ext2 (rw,acl,user_xattr)
> 
> Do you believe I will notice a performance problem lets say with 500.000 
> files in one directory?
> 
> Best regards,
> 
> Merlin

If you once have 500000 files in a directory, it will be terrible slow to
do ls , even after you delete 499999 of them, since the directory itself
will be huge, and never shrink when removing files.
The only way to clean it is to make a new directory.

If your application know the name and call the file, it will not be so slow,
it's just the other way, when listing the contents of a directory.

Reiserfs is better to handle this, and if you turn off acl and xattr you make
it a bit faster. (unless you need those features)

/bb