Disk-Performace issue?

Charles Swiger cswiger at mac.com
Tue May 10 05:21:13 PDT 2005

On May 10, 2005, at 6:46 AM, Michael Schuh wrote:
> Now i have 2 Directories with ~500.000-600.000 files with an size of 
> ~5kByte.
> by copying the files from one disk to another or an direktory on the 
> same disk
> (equal behavior), i can see this behavior:
> [ ... ]
> Can anyone explain me from where this behavior can come?
> Come thie eventually from the filesytem, or from my disks, so that
> these are to hot? (I think not)

Directories are kept as lists.  Adding files to the end of a list takes 
a longer time, as the list gets bigger.  There is a kernel option 
called DIRHASH (UFS_DIRHASH?) which can be enabled which will help this 
kind of situation out significantly, but even with it, you aren't going 
to get great performance when you put a half-million files into a 
single directory.

Try breaking this content up into one or two levels of subdirectories.  
See the way the Squid cache works...


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