On Wed, Mar 26, 2008 at 3:30 PM, Marcus Kool <marcus.kool@xxxxxxxxxxxxxxx> wrote: > > The point of why I started the discussion is that the statement in the wiki > "Do not use RAID under any circumstances" is at least outdated. Well, it says: "Don't". Agreed, it's a bit radical. You're welcome to edit the wiki if you wish, just let me know your wiki username so that I may give you write access. > Most companies will trade in performance for reliability because they depend > on internet access for their business and cannot afford to have 2-48 hours > of unavailability. I'm not going to argue with that. The point is that usually there are more cost-effective ways to get the same level of reliability if not more. For instance, going JBOC (Just a Bunch Of Caches) with load-balancing/high-availability mechanisms (Proxy PAC/WPAD or Linux Virtual Server with or without VRRP or any other Layer 2-4 load balancing solution) is a very effective system to get very high reliability. > Everybody knows that EMC and HP systems are much more expensive than > a JBOD but this is not a valid reason to say "Never use RAID". > "Never use RAID" implies that RAID is *BAD* which is simply not true. > > From my point of view, the wiki should say something like: > > If you want cheapest, modest performance, with no availability guarantees use JBOD. > If you want cheap, modest performance and availability use RAID1/RIAD5 without > a sophisticated disk array (preferably with a RAID card that has > 128+ MB battery-backed write cache). > If you want cheapest availability use RAID5 without a sophisticated disk array > If you want expensive extreme performance and availability use a sophisticated disk array. Agreed, it can be improved. The point that should be driven across is that rather than spending 1kEur for a HW RAID SCSI Controller + 5KEur for the disks to go with it, it's much more cost-effective to spend 2KEur for a second server and use VRRP. -- /kinkie
