Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!drn.maxwell.syr.edu!news.maxwell.syr.edu!feed.news.tiscali.de!fu-berlin.de!newsfeed.iinet.net.au!newsfeed.iinet.net.au!per-qv1-newsreader-01.iinet.net.au!not-for-mail Message-ID: <4251267B.3781@yahoo.com> Date: Mon, 04 Apr 2005 19:35:23 +0800 From: Connor McDonald Reply-To: connor_mcdonald@yahoo.com X-Mailer: Mozilla 3.01 (WinNT; I) MIME-Version: 1.0 Newsgroups: comp.databases.oracle.server Subject: Re: Exotic Blocksize 6144 Byte References: <424CCD7A.E2340BC9@t-online.de> <1112510501.504371.188120@g14g2000cwa.googlegroups.com> <3kN3e.728410$b5.32921904@news3.tin.it> <1112549913.521880.61910@z14g2000cwz.googlegroups.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 39 NNTP-Posting-Host: 203.59.217.138 X-Trace: 1112614523 per-qv1-newsreader-01.iinet.net.au 19139 203.59.217.138 Xref: dp-news.maxwell.syr.edu comp.databases.oracle.server:239588 Mark D Powell wrote: > > I do not claim to be familiar with the details of the NTFS file system > structure but if I remember from the manuals that covered formatting my > new harddrive back in the days when you upgraded PC rather than buy new > ones the 512k chunk on disk was the device sector size. The OS > however, reads and writes multiple secotrs at a time. This grouping of > sectors was called a cluster and generally was 2k, 4k, or 8k worth of > sectors at a time. On any other system except Windows the cluster size > would be called the block size. The cluster size dedended on the > size/mdoel of the disk drive and how it was partitioned. > > If the OS block size is 4K the two OS IO are required for every Oracle > IO and 25% of the IO is wasted since it is not part of the requested > Oralce block(s). This would be bad. If on the other hand the OS IO > size is 6k then the 6k size choice for Oracle was probably a good one > in the past. Since the manuals refer to Oracle only officially > supporting 4k, 8k, 16k, and 32k you may want to determine what the real > OS IO size is and match the database to it. > > -- Mark D Powell -- I suppose using a "non-power-of-two" blocksize does give you access to an additional cache...although I would imagine its a pretty specialist requirement to have a database that explictll needs that extra cache :-) -- Connor McDonald Co-author: "Mastering Oracle PL/SQL - Practical Solutions" Co-author: "Oracle Insight - Tales of the OakTable" web: http://www.oracledba.co.uk web: http://www.oaktable.net email: connor_mcdonald@yahoo.com "GIVE a man a fish and he will eat for a day. But TEACH him how to fish, and...he will sit in a boat and drink beer all day" ------------------------------------------------------------