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Paul Koufalis
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Ahh...a repeat of DBA Day in Ontario...I respectfully disagree, except for the part where you have to get those archived AI files out to a different data centre in a different city ASAP. If everything is on the SAN, I'm not sure if there is still a performance gain to having the AI files on a separate FS if the underlying LUNs are all writing to the same SAN and SAN cache. Maybe there is, but probably only at a very high write rate. There USED to be issues on AIX with large LUNs and benefits to having separate FS, but those were bugs that have since been fixed. Maybe other O.S.'s still suffer from these issues. I will concede that if your bean counters insist on RAID 5 for the DB (don't worry, the vendor said it's GRRRREAAT!!"), you can try to negotiate RAID 10 LUNs for the AI/BI. If it's a small site with local disks in the physical server, my argument is that I need to maximize the use of ALL the spindles. A physical box with eight 2.5" bays is not going to perform optimally if I reserve two in mirror for the operating system, two in mirror for the AI files and four in RAID 10 for the data files. Note that there's no room for a hot spare disk here either. I am going to put all 8 bloody drives in one big RAID 10 and maximize my throughput. At least SSDs are fast becoming affordable. Paul
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