> -----Original Message----- > From: Roman Mamedov [mailto:roman@xxxxxxxx] > Sent: Saturday, July 17, 2010 4:31 PM > To: Leslie Rhorer > Cc: linux-raid@xxxxxxxxxxxxxxx > Subject: Re: Changing Chunk Size on Array > > On Sat, 17 Jul 2010 16:15:55 -0500 > "Leslie Rhorer" <lrhorer@xxxxxxxxxxx> wrote: > > > > > I'm thinking about changing the chunk size on one of my arrays in > > order to potentially improve performance. The man page rather suggests > -c > > is a vlaid option under Grow mode, although it doesn't specifically say > > mdadm supports it under --grow. Is it indeed supported under mdadm > 2.6.7.2 > > and kernel 2.6.26-2? Assuming so, I would like to know a bit more about > the > > change before issuing the command. Speficialy, what are the details of > the > > process? Does the entire (RAID 6) array have to be re-written, such as > is > > the case with adding a drive to the array? Does the recovery start > > immediately? Can it be interrupted and then continue at a later time? > > Out of curiosity, which chunk size do you have, and which you want to > change > it to, and do you expect the new size to be faster based on any tests? The current chunk is 256K. One of my other arrays on a nearly identical platform seems to have better performance at 1024K. I haven't made any decisions, yet on what the new value would be, or even in fact if I will actually consider doing it. I'm still at the evaluation stage. Most of the files on the array are in the 10G - 30G range in size, and they are generally read and written sequentially. The individual members are thirteen 1T drives in an 11T RAID6 array. -- 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
