On 10/31/2012 03:59 PM, Kushnir, Michael (NIH/NLM/LHC) [C] wrote: > I am working with several Dell PE720xd. I have 24 disks per server at my > disposal with a high end raid card with 1GB RAM and BBC. I will be building a > distributed-replicated volume. Is it better for me to set up one or two large > RAID0 arrays and use those as bricks, or should I make each hard drive a brick? > > This will be back end storage for an image search engine with lots of small > file reads from multiple application servers. As a very general rule, the "one big RAID" type of configuration will work a little better, especially for workloads where accesses to blocks within the same RAID stripe will come close together - large requests, sequential requests, requests with some other locality of reference. For workloads lacking that characteristic, the "many small bricks" approach - essentially letting GlusterFS manage scheduling instead of the RAID controller - might work better. However, there are so many exceptions both ways that no rule of thumb really suffices. I highly recommend running your workload or a close simulation of it on both configurations, to see which really performs better for your I/O patterns on your hardware. It's worth the effort.
