Re: [LI] Question regarding the Linux file system i/o

[C Hanish Menon <hanish@xxxxxxxxxxxxxxxxxx>]

Hi

On Sat, 27 Nov 1999, Satya wrote:
> 2. Is there a recommend limit on the number of files in a single directory?
> When does the performance of the file system degrades?

Based on the way the Directories are handles in ext2 there shouldn't be any
limit on the number of entries in a directory.  However if the number of files
is very large the time taken to get info regarding a file (as required during
a open call) may be large for 2 reasons.

	a) The number of DiskBlocks required to be accessed to get the directory
entry for the file.

	b) The search algo used for getting the required directory entry.  ( I
haven't varified). Many fs use simple linear search which is good for many
cases but not for directories with a large number of files.

Well the buffering/caching  if used for directory entries would help reduce the
time taken. (I haven't varified).

> 3. Has any body doen experiment on - database query v/s file system i/o
> (seek - basically)? Which one is recommended - though my gut feeling says it
> is database (I am using Oracle 8)
> 

Even thou one can get better performance for specific purposes by writing
direct routines to access Diskblocks or so, Given the advantage of portability
and the different Data access requirements of a app a Database would be
good PRACTICAL alternative.

---------
Keep :-)
HanishKVC
--------------------------------------------------------------------
The Linux India Mailing List Archives are now available.  Please search
the archive at http://lists.linux-india.org/ before posting your question
to avoid repetition and save bandwidth.