what about mirroring only ? raid 1 ? I always thought that raid 1 is the fastest, am I true ?
I don't really need more then 3GB data and I have two 36GB HD. so I don't need lvl 0 nor lvl 5 unless raid 1 is slower. -------------------------- Canaan Surfing Ltd. Internet Service Providers Ben-Nes Michael - Manager Tel: 972-4-6991122 Fax: 972-4-6990098 http://www.canaan.net.il -------------------------- ----- Original Message ----- From: "Markus Wollny" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Tuesday, October 21, 2003 11:00 AM Subject: Re: [GENERAL] Recomended FS > Theory vs. real life. In Theory, RAID5 is faster because less > data have > to be written to disk. But it's true, many RAID5 controllers > don't have > enough CPU power. I think it might not be just CPU-power of the controller. For RAID0+1 you just have two disc-I/O per write-access: writing to the original set and the mirror-set. For RAID5 you have three additional disc-I/O-processes: 1. Read the original data block, 2. read the parity block (and calculate the new parity block, which is not a disk I/O), 3. write the updated data block and 4. write the updated parity block. Thus recommendations by IBM for DB/2 and several Oracle-consultants state that RAID5 is the best compromise for storage vs. transaction speed, but if your main concern is the latter, you're always best of with RAID0+1; RAID0+1 does indeed always and reproducably have better write performance that RAID0+1 and read-performance is almost always also slightly better. ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
