From: Steve Phelan Subject: Re: RAID configuration for Oracle7 Date: 1997/03/03 Message-ID: <331B0CA2.2731@pmcgettigan.demon.co.uk>#1/1 X-NNTP-Posting-Host: pmcgettigan.demon.co.uk References: <3318faca.11999432@news.centroin.com.br> <3315C116.5448@geocities.com> Organization: Toneline Ltd. Reply-To: stevep@pmcgettigan.demon.co.uk Newsgroups: comp.databases.oracle.misc > Oracle is a RDBMS robust and secure against system failures, so RAID 5 > security my be redundant and a cause for I/O contention. Oracle is recoverable, but RAID 5 is resilient. If you loose a disk on a non-RAID (or non mirrored) system, you have to recover - a RAID system, especially if configured with a 'hot spare' is tolerant to this type of failure without interuption, and will auto rebuild. A RAID 5 system will *generally* give an improvement in READ performance at the expense of WRITE performance. Note: you should generally avoid software RAID implementations, as the overhead is usually very high. You should really *test* your RAID system to see if it fits *your* needs. As regards redo and temp: in a very heavy OLTP environment the overhead of WRITING the parity info may force you to place these systems on a non-RAID 5 system. Note you can still use RAID, but not necessarily RAID 5 (say RAID 1, mirroring) to give you some protection for redo and temp placed on these disks. Look in the Oracle Advanced Tuning and Admin book as well as the Oracle Datawarehousing book for more info on choosing a suitable RAID setup for your system, as there is no 'golden' answer to your question without knowing the exact requirements of your system. Steve Phelan.