Informix DSA and RAID 5

We run several databases using RAID3 and 5. The big savings is in the amount of disks needed compared to mirroring (RAID1). We see a small performance loss but it is not significant enough to warrant going to mirroring. The database sees the RAID set as a device. It does not know there is anything special about it. You can mix RAID types to allow for tuning (such as fragmenting). In our largest database we have a RAID3,a RAID5 and several RAID1 sets. If possible you want to keep the Informix overhead (root, logs, temp space) on mirrors. The striping of them can drag you down. If you have any highly volatile tables in your application you will probably want them on mirrors also. You have to check with your RAID vendor to see if they allow multiple RAID types in the same cabinet. My practical RAID3-5 experience is limited to DEC Storageworks hanging off of HP-UX. Scott Patterson Sr. DBA NORAND Corp pattersons@norand.com ______________________________ Forward Header __________________________________ Subject: Informix DSA and RAID 5 Author: jason.baines@bradford.gov.uk (Jason A. Baines) at smtpgate Date: 5/7/97 9:47 AM Can anybody shed any light on the advantages / disadvantages of using RAID 5 technology with our Informix DSA system. ie somebody told me that the optimiser might not perform to its full benefits and table fragmentation would not be as useful. Any comments ?? Jason.