On Tue, May 13, 2008 at 8:00 AM, Francisco Reyes <lists@xxxxxxxxxxxxxxxx> wrote: > PFC writes: > > > > You say that like you don't mind having PCI in a server whose job > is to perform massive query over large data sets. > > > > I am in my 4th week at a new job. Trying to figure what I am working with. > From what I see I will likely get as much improvement from new hardware as > from re-doing some of the database design. Can't get everything done at > once, not to mention I have to redo one machine sooner rather than later so > I need to prioritize. > > > > > In fact for bulk IO a box with 2 SATA drives would be just as fast as > your monster RAID, lol. > > > > I am working on setting up a standard test based on the type of operations > that the company does. This will give me a beter idea. Specially I will work > with the developers to make sure the queries I create for the benchmark are > representative of the workload. > > > > > Adding more drives will help random reads/writes but do nothing for > throughput since the tiny PCI pipe is choking. > > > > Understood, but right now I have to use the hardware they already have. > Just trying to make the most of it. I believe another server is due in some > months so then I can better plan. > > In your opinion if we get a new machine with PCI-e, at how many spindles > will the SCSI random access superiority start to be less notable? Specially > given the low number of connections we usually have running against these > machines. > > > > > However RAID5 will choke and burn on small random writes, which > will come from UPDATing random rows in a large table, updating indexes, > etc. Since you are doing this apparently, RAID5 is therefore NOT advised ! > > > > I thought I read a while back in this list that as the number of drives > increased that RAID 5 was less bad. Say an external enclosure with 20+ > drives. maybe, but I don't think very many people run that many drives in a raid 5 configuration...too dangerous. with 20 drives in a single volume, you need to be running raid 10 or raid 6. 20 drive raid 50 is pushing it as well..I'd at least want a hot spare. merlin
