On Mon, Feb 03, 2020 at 01:48:20PM -0800, Alan Latteri wrote: > Hello, > > In an environment with an LSI 3108 based HW-RAID60, 256k stripe size on controller, 5 spans of (10data+2parity) disks. What is the proper su & sw to use? Do I do sw to the underlying 10 data disks per span? The top level 5 spans or all 50 data disks with the array? Use case is as a file server for 20-60 MB per frame image sequences. > > i.e > > 1) sw=256k,sw=10 > 2) sw=256k,sw=5 > 3) sw=256k,sw=50 A HW RAID6 lun in this configuration behaves (and performs) like a single disk, so you're actually putting together a 5-disk raid-0 stripe with a stripe unit of 2560kB. i.e. for consistent performance and allocation alignment for large files, you want to do full RAID-6 stripe writes to each lun. Hence you want the filesytsem aligned to the first disk in each of the RAID-6 luns and to size allocations to full RAID6 lun width, not random individual drives in the RAID-6 luns. IOWs: sw=2560k,sw=5 Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
