F
frank.meulblok
Guest
If you want to sum up the above in more non-technical terms: 1. RAID-5 sacrifices write speed by design. 2. Every change to your data will get written to disk at least 3 times (persistent storage because that's what a DB is for, before-image and backup in case something goes wrong), often 4 times (after imaging). If you want to get rid of those extra writes: DON'T. They're your basic safeguard to ensure you can recover when something goes wrong. Conclusion: RAID-5 guarantees your database performace will suffer when you reach a certain level of create-update-delete workload. 3. When something goes wrong and you need to recover, restoring the system will cause a lot of disk writes that need to happen as fast as possible to minimize downtime. Because downtime only costs money and doesn't gain any. Conclusion: RAID-5 will turn any disaster into a bigger disaster.
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