On 7 June 2012 03:51, Ole Tange <ole@xxxxxxxx> wrote: […] > So Igor: Do you have numbers that back up your claim? Or do you advice > against it just because "it's simply stupid"? The reasons are pretty well described in FreeBSD 4.11 vinum's manual (which I had been using long before LSR): «… For optimum performance, stripes should be at least 128 kB in size: anything smaller will result in a significant increase in I/O activity due to mapping of individual requests over multiple disks. The performance improvement due to the increased number of concurrent transfers caused by this mapping will not make up for the performance drop due to the increase in latency. A good guideline for stripe size is between 256 kB and 512 kB. Avoid powers of 2, however: they tend to cause all superblocks to be placed on the first subdisk. …» — http://goo.gl/sTHxY P. S. Alas, LSR doesn't support anything but powers of 2 for chunk sizes, but according to Neil Brown, it can be relatively easy changed. -- -- 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
