On 5/24/2013 1:32 AM, keld@xxxxxxxxxx wrote: > On Thu, May 23, 2013 at 10:45:56PM -0500, Stan Hoeppner wrote: >> On 5/23/2013 3:30 AM, keld@xxxxxxxxxx wrote: >>> On Thu, May 23, 2013 at 12:59:39AM -0500, Stan Hoeppner wrote: >> >>>> You may be tempted to use md/RAID10 of some layout >>>> to optimize for writes, but you'd gain nothing, and you'd lose some >>>> performance due to overhead. The partitions you'll be using in this >>>> case are so small that they easily fit in a single physical disk track, >>>> thus no head movement is required to seek between sectors, only rotation >>>> of the platter. >> ... >>> I think a raid10,far3 is a good choice for swap, then you will enjoy >>> RAID0-like reading speed. and good write speed (compared to raid6), >>> and a chance of live surviving if just one drive keeps functioning. >> >> As I mention above, none of the md/RAID10 layouts will yield any added >> performance benefit for swap partitions. And I state the reason why. >> If you think about this for a moment you should reach the same conclusion. > > I think it is you who are not fully aquainted with Linux MD. Linux > MD RAID10,far3 offers improved performance in single read, On most of today's systems, read performance is largely irrelevant WRT swap performance. However write performance is critical. None of the md/RAID10 layouts are going to increase write throughput over RAID1 pairs. And all the mirrored RAIDs will be 2x slower than interleaved swap across direct disk partitions. -- 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
