Re: Database and RAID

Hi Udo, This is a question that is commonly asked, and the answer is always the same. The hardware vendors keep saying RAID is the fastest system. But it isn't true. The fastest way is to use mirrored dbspaces (mirrored by informix) because Informix writes in parrallel and for reading it can use both disks the primary and the mirror. If the primary disk is busy the mirror is used. The problem with RAIS is that inserts are much slower because of the extra overhead for example compressing as to be done. There is only one faster alternative and that are disk-array's from for example EMC^2. These systems are very fast beacuse they have a lot of cache inside. I hope this has hepled you. Greetings, Rob Prop Database Consultant Informa Automatisering BV (Netherlands) Syed <sas@mastic.gov.my> wrote in article <6m4poo$1i1$1@news.xmission.com>... > > This is what i always wanted to know as well. At the moment we also need > to decide either to use Database mirroring option or RAID system. I was > told by the hardware engineer that using RAID system is much safer since > failure other than the database will be taken care. I was also told that > any problem in the database will prompt for the RAID system to switch to > the mirrored harddisk, i am not sure to what extend this is done. I was > asking if the space allocated for Online system is full, or any chunk is > down can the RAID system take care, he was unable to assure, but said > that there must be a way to take care those problem. We decided to go > for RAID system, only after the system alive which i expect to be > somewhere in August i will be able to know the performace. I would also > much appreciate any input on this matter. > > Syed. > > Udo Scholz wrote: > > > > Does anyone have practical experiences in using RAID systems and > > database servers? > > > > Is it either better to use mirrored harddisks and distribute datas wich > > the advanced features of the according database server (for instance > > Sybase ASE) or simplify this overhead by using a RAID5 system? > > > > Interesting facts are: performance, security, handling and so on. > > > > Thank you for useful answers, hints ... > > -- > > > > Udo Scholz > > > > BB-DATA GmbH > > Planung & Projekte / Datenhaltung (PPDA) > > Brunnenstrasse 111, DLZ A2.32, 13355 Berlin > > email: udo.scholz@bb-data.de > > Tel.: (030) 245 - 54472 > > Fax: (030) 245 - 580 54472 oder 245 - 54921 > > > > -- > > -- > Syed Ibrahim > Sapura Advanced Systems Sdn. Bhd, 18th Floor, Menara Tun Razak, Jalan > Raja Laut, 50350 Kuala Lumpur, Malaysia > Tel: (03) 295-3472, (03) 294-3000 Fax: (03) 294-6587, (03) 293-3154 >