On 9/24/14 10:53 AM, Helmut Tessarek wrote: > On 2014-09-24 0:09, Stan Hoeppner wrote: >> If you create any striped arrays, especially parity arrays, with md make >> sure to manually specify chunk size and match it to your workload. The >> current default is 512KB. This is too large for a great many workloads, >> specifically those that are metadata heavy or manipulate many small >> files. 512KB wastes space and with parity arrays causes RMW, hammering >> throughput and increasing latency. > > Thanks again for the valueable information. > > I used to work with databases on storage subsystems, so placing GBs of > database containers for tableapaces on arrays with a larger stripe size > was actually beneficial. > For log files and other data I usually used different cache settings and > strip sizes. > > So how does this work with SW RAID? > > Does the XFS chunk size equal the amount of data touched by a single r/w > operation? It has more to do with where allocations start, so that allocations don't cross stripe boundaries if possible. -Eric _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
