This technique, also called RAID 1+0, is often used in database installations. The basic logic is that with 4 or more drives you can get the redundancy of RAID 1 with the performance of RAID 0. RAID 5 generally has poor performance for database use. If you have a hardware RAID card let it do the mirroring (reduces bandwidth on the PCI bus) and let the OS do the striping. This would require 2 RAID 1 mirror sets, then striping to those virtual devices. Theoretically in a 4 drive setup you could tolerate 2 drive failures if the drives are in different mirror sets. Personally I would use Linux software RAID to create the RAID 0, then create the LVM volumes on top of that. I'm currently planning this type of installation, but I've not received the hardware yet, so I can't tell you my experience. This has been talked about extensively on the PostgreSQL performance mailing list. Check out this thread. Jord Tanner On Thu, 2004-01-08 at 03:01, Ricardo Mattia wrote: > Hello. > > Today we have a host running Oracle 8.1.7 on AIX 4.3.3. > We decided to migrate this system from RISC to Intel and the > choosed operating system was SUSE Linux. > Besides that, we are changing the way Oracle Datafile's are > distributed. After some internet research, we got in touch with a > methodology called S.A.M.E, which stands for Stripe and Mirror > Everything. > Basicaly, we need to Stripe all the storage available using LVM > (on operating system level) and mirror everything (on storage level). Of > course we increase our risk of an entire system failure in case of just > "one" RAID crash. > This methodology is explained on Juan Loaiza's whitepaper, from > Oracle Corporation. > > So, my question is : Has anyone implemented this stuff using > Linux SUSE and LVM? If yes, is it work and could you give me some tips > about it? > > Thanks in advance. > > Best Regards, > Ricardo Mattia > http://www.rge-rs.com.br > 51 3218-3168 > > > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ -- Jord Tanner <jord@indygecko.com> _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
