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Re: slow handling of large sets of files?
- From: Ken Sheldon <Ken_Sheldon at ACM dot org>
- To: cygwin at cygwin dot com
- Date: Tue, 01 Feb 2005 13:28:50 -0600
- Subject: Re: slow handling of large sets of files?
I too have been seeing a problem with very slow file access in large
directories.
Specifically,
On a Cygwin/Win2k box, I have a mirror of an FTP site. The site has 2.5
million files spread between 100 directories.
(20,000 - 30,000 files per directory) I have previously run this number
of files in an NT4 NTFS filesystem without significant performance
problems.
In this site, operations like these are __VERY__ slow.
ls ${some_dir}
ls ${some_dir}/${some_path}
cp ${some_file} ${some_path}
cp -R ${some_path_with _only_a_few_files} ${some_path}
If I look at the performance monitor, I can see a queue depth of 1-2 and
300-500 disk reads per second. (That's real. It's a fast array) The
reads appear to be single-block reads, as the throughput during these
events is 1.5 - 3MB/sec.
I am beginning to think the disk activity relates to NTFS permission
checking, which can be complex under Win2k.
I don't know how to debug or tune this.
Any ideas?
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