diff --git a/docu/mars-user-manual.lyx b/docu/mars-user-manual.lyx index ce491a32..0e68d53d 100644 --- a/docu/mars-user-manual.lyx +++ b/docu/mars-user-manual.lyx @@ -25070,6 +25070,12 @@ re-ordering of writeback transaction logfile, and even when both are residing at the same RAID set. \end_layout +\begin_layout Standard +Since RAID-6 is has more expensive write operations due to its CRC computations + and updates, RAID-6 will much more profit from this effect. + Other RAID modes like RAID-10 may show a lower throughput improvement. +\end_layout + \begin_layout Standard Notice: this effect is not only dependent from total RAM size and from the maximum size of the MARS temporary memory buffer (tuning parameter @@ -25098,6 +25104,17 @@ dd is no appropriate benchmarking tool, and has almost nothing to do with real workloads occuring in datacenters, which typically are neither sequential, nor do they have a parallelism degree of only 1. +\end_layout + +\begin_layout Standard +\noindent +\begin_inset Graphics + filename images/MatieresCorrosives.png + lyxscale 50 + scale 17 + +\end_inset + Please don't try to lead any discussions about this: simply use \family typewriter blktrace @@ -25123,11 +25140,20 @@ dd \end_inset - Any assumptions about workloads are very dangerous: they can deviate from - practice not only by factors, but sometimes even by + Any +\series bold +assumptions about workloads +\series default + are very dangerous: they can deviate from practice not only by factors, + but sometimes even by \emph on orders of magnitude \emph default +. + There no substitute for real measuments of +\series bold +actual workload behaviour +\series default . \end_layout