From cspence@FuelSpot.com Thu, 06 Sep 2001 06:59:35 -0700 From: Christopher Spence Date: Thu, 06 Sep 2001 06:59:35 -0700 Subject: RE: Max IO size - File System vs Raw Message-ID: MIME-Version: 1.0 Content-Type: text/plain A lot of file system's have a max io of much lower than raw. In the earlier Solaris's it was 64K, but as you see, it is now seems to be 256k. Under NT is 128k without using raw. To truly take advantage of MULTIBLOCK_READ_COUNT you need to use RAW file system. HP_UX I believe can do as high as 1Mb for this. "Do not criticize someone until you walked a mile in their shoes, that way when you criticize them, you are a mile a way and have their shoes." Christopher R. Spence Oracle DBA Phone: (978) 322-5744 Fax: (707) 885-2275 Fuelspot 73 Princeton Street North, Chelmsford 01863 -----Original Message----- Sent: Thursday, September 06, 2001 9:11 AM To: Multiple recipients of list ORACLE-L Anyone know of any restrictions on the max physical IO (under Solaris8) that is imposed by file systems? To illustrate - Using a tablespace on a raw device under veritas vol mgr - maxphys is 512k - vxio:vol_maxio is 512k - db block size is 8k - db multi read is 64 and as expected, a level 8, 10046 trace shows me that I can get 512k max io...so far, so good If I repeat the exercise after putting a file system (vxfs or ufs) on this device, then the best I can get is 256k. Any Solaris internal people out there ? Cheers Connor ===== Connor McDonald http://www.oracledba.co.uk (mirrored at http://www.oradba.freeserve.co.uk) "Some days you're the pigeon, some days you're the statue" ____________________________________________________________ Do You Yahoo!? Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk or your free @yahoo.ie address at http://mail.yahoo.ie -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: =?iso-8859-1?q?Connor=20McDonald?= INET: hamcdc@yahoo.co.uk Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Christopher Spence INET: cspence@FuelSpot.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).