From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: DNS server reading directly from reiserfs Date: Thu, 02 May 2002 14:37:17 +0400 Message-ID: <3CD116DD.5010808@namesys.com> References: <20020502103932.GA23420@vega.ipal.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Phil Howard Cc: reiserfs-list@namesys.com Phil Howard wrote: >Continuing from an earlier discussion I had regarding the use of reiserfs >based files in place of databases, I was thinking about the issues involved >in serving DNS data directly from files. The concern I had previously was >the performance hit from open(),read(),close() to access a single piece of >data to answer a query. Today I realized that DJBDNS uses the CDB format >and does an open(),read(),close() sequence for each query as well. So it >can't be that bad. This would come down to reiserfs vs CDB for which is the >faster in finding the desired piece of data, not the syscall interfaces, in >terms of comparing these two. Assuming all data is in a single directory, >or maybe is in a directory tree structured TLD-first, what performance level >might one expect doing this? With ext2 it could be quite costly due to the >O(N) lookup. With reiserfs tree structure, this would be a lot better. And >with tail-packing, less RAM would be needed to keep lots of data in cache >for large servers. Any thoughts or benchmark data along these lines? > > > You never know until you measure. Try it! Hans