On 6/14/2014 4:01 PM, Nuno Magalhães wrote: ... > This is a desktop system, nothing > mission-critical, but i'd like it to be reasonably tailored to the > hardware and intended usage, and have questions about default values. [snip] Everything begins and ends with the workload. The proper chunk and stripe sizes are dictated by the write patterns of your workload, i.e. the mix of applications running on the system, not the type/size of disks you have. If you're writing lots of small files then you'll typically want a small chunk size. If you use a large chunk size with small files you'll get a hot spot on one or more drives in the array due to filesystem alignment. Hot spot means one disk sees lots of activity while the other(s) sit idle. This defeats the purpose of striping. If you're working predominantly with large media files you'll want a large chunk/stripe for data transfer efficiency from the platters with the fewest seeks. If you have a mixed workload with small and large files, it's best to use a small chunk size, such as 32 or 64KB. All of that stated, your filesystem setup, specifically write barrier support and journal mode, along with those slow disk spindles, will be a much more significant impediment to performance than your chunk size. Cheers, Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
