Re: OLTP File Placement???

From: dave mausner <dmausner_at_ameritech.x.net>
Date: Fri, 07 Jan 2000 04:05:17 GMT
Message-ID: <8EB3E496Bdlm@206.141.192.241>

me_at_me.com (me) wrote in <P4Qc4.9$L3.1610_at_news.onlynews.com>:

>I've heard that the O/S should be on a mirrored drive. Database files
>should be on a RAID5 array. Redo Log files should be on a mirrored drive
>array. Anything I'm missing or that you care to suggest would be greatly
>appreciated.

it's a religious issue. if your machine can possess both raid-1 (mirror) and raid-5 (striped) arrays, i would argue that you are just wasting drives by using mirrors. make the entire array raid-5 if any of it is raid-5.

otoh, if you want better performance at the cost of drives, use only raid- 1. i have found that raid-5 is slower on updating than for reading. the reason could be checksum overheads, but more likely it's because all the heads are moving all the time, increasing the average latency a little. with mirrors, the heads can probably settle over the hot zone. (0.02) --
dave mausner Received on Thu Jan 06 2000 - 22:05:17 CST