On Fri, 07 Mar 2014 18:30:13 +0100, Cedric Lemarchand <cedric@xxxxxxxxxxx> wrote: > Le 07/03/2014 18:05, Stijn De Weirdt a écrit : > > we tried this with a Dell H200 (also LSI2008 based). > > > > however, running some basic benchmarks, we saw no immediate difference > > between IT and IR firmware. > > > > so i'd like to know: what kind of performance improvement do you get, > > and how did you measure it it? > IMO, flashing to IT firmware is mainly done to get the JBOD feature, > which most of the time lacks with IR. > That was the reason we did it. Machine originally had LSI2108 (that we replaced with 2008) that didn't had ANY JBOD mode so adding disk was a pain (we had to add raid0 with one disk to make controller present disk to OS). In addition to that any disk errors were "handled" by controller and by "handling" i mean completely disconnecting it from OS, which was problematic. IT mode benefit is that all IO errors are send to OS "as is" so whatever you use can handle errors. In case of Linux software raid it can remap some sectors before completely failing and at least lets you get a replacement disks ready before disk fails completely -- Mariusz Gronczewski, Administrator efigence S. A. ul. Wołoska 9a, 02-583 Warszawa T: [+48] 22 380 13 13 F: [+48] 22 380 13 14 E: mariusz.gronczewski@xxxxxxxxxxxx <mailto:mariusz.gronczewski@xxxxxxxxxxxx>
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