On 09/13/2012 12:05 PM, Joe Landman wrote: > On 09/13/2012 11:21 AM, [email protected] wrote: >> >>> I assume so, but just to be clear you witnessed this behavior even with >>> the -I (directio) parameter? >> >> Yes. >> >> for i in 1 2 4 8 16; do /cm/shared/apps/iozone/current/sbin/iozone -I -l >> $i -u $i -r 16k -s 10M -F file1..file16 ; done> output& > > -s 10M ??? > > This is a 10M test file size. > > Ok. Let me be clear, 10M as a file size is not useful as a test. The > numbers are, for lack of any better way to describe this, meaningless. > > From the iozone man page > > -s # Used to specify the size, in Kbytes, of the file to > test. One > may also specify -s #k (size in Kbytes) or -s #m > (size in > Mbytes) or -s #g (size in Gbytes). > > > If each storage node has 128GB ram (I think this was the number) and you > want a "serious" (as in real) test, you need to take your N storage > nodes @128GB each, sum up the ram, double it, and that is your file > size. When you have that, your performance numbers will be uncached, > and therefore far more likely to represent the actual hardware performance.
I must be filtered out by Joe's email software or something...I said almost verbatim this very suggestion now an hour or more ago. :/. Best, ellis _______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
