Xref: alice comp.databases.oracle.tools:33418 Path: alice!news-feed.fnsi.net!newspump.monmouth.com!newspeer.monmouth.com!newsfeed.enteract.com!chicago-news-feed1.bbnplanet.com!news.gtei.net!news.itis.com!tower.itis.com!encephal From: "Andrew L. Garman" Newsgroups: comp.databases.oracle.tools,comp.unix.solaris Subject: Re: Oracle and Veritas Date: Sun, 10 Oct 1999 12:39:35 -0500 Organization: IntraNet Inc: Madison, Wisconsin's ISP Lines: 34 Message-ID: References: <37FCCE12.F2E3EE87@bmo.com> <7tj0m8$9df$1@nnrp1.deja.com> <7tlnpk$8qe$1@carlton.cubbyhole.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Sender: encephal@tower.itis.com In-Reply-To: <7tlnpk$8qe$1@carlton.cubbyhole.com> > > The database edition really improves Direct (ie, synchronous) I/O access > > for the database. > Is this still true? I thought Solaris 2.6 had changes to the UFS file > system to make databases on partitions almost as fast as raw devices? Sun's UFS+ with logging, direct I/O, etc will probably be pretty slow in comparison. Mostly, VxFS being an extent based filesystem has major advantages for synchronous sequential writes to start with. UFS+ still uses Inode to Datablock allocation, which requires many inode lookups before reaching the data. And the datablocks aren't likely contiguous on the disk. Whereas with an Extent based file system, you have a single inode pointing to multiple MB of data all of which is contiguous. VxFS Quick I/O for Oracle also provides customized caching that improves Oracle disk access. This will enable better than raw performance on synchronous I/O, between 120-180% according to reports I've read, though I've not seen it in operation. The first version gave about 98% of Raw performance, which was better than I could get from tweaked UFS+. There is no asynchronous I/O on raw Solaris devices. > And now with priority paging, shouldn't that level the playing field even > more? Priority paging wouldn't be an advantage to UFS+ at least not one that VxFS doesn't benefit from as well. Regards, Andrew Garman Bluestone Consulting, inc.