2011/2/3 Keld Jørn Simonsen <keld@xxxxxxxxxx>: > On Thu, Feb 03, 2011 at 01:50:49PM -0200, Roberto Spadim wrote: >> hummm, nice >> keld (or anyone), do you know someone (with time, not much, total time >> i think it?s just 2 hours) to try develop modifications on raid1 >> read_balance function? > > maybe our very productive Polish friends at Intel could have a look. > But then again, I am not sure it is productive. I think raid1 is OK, > You could have a look at raid10, where "offset" has been discussed as > being the better layout for ssd. ok, i think that there´s no 'better' layout for ssd since ssd don´t have a variable access time like head on hard disk it´s better because today read balance is optimized for minimal distance (nearest head) but it´s not true that layout for ssd is better >> what modification, today read_balance have distance (current_head - >> next_head), multiply it by a number at /sys/block/md0/distance_rate, >> and make add read_size*byte_rate (byte_rate at >> /sys/block/md0/byte_read_rate), with this, the algorithm will make >> minimal time, and not minimal distance >> with this, i can get better read_balance (for ssd) >> for a second time we could implement device queue time to end (i think >> we will work about 1 day to get it working with all device >> schedulers), but it?s not for now > > Hmm, I thought you wanted to write new elevator schedulers? no, it´s not a elevator, it´s a raid1 read balance, based on time (each sda,sdb,sdc,sdd can have you elevator without problem) it´s like a elevator for raid1 (mirror), some other raid could use it too (raid10, i don´t know if raid5 have mirror, but if yes, could use too) > > best regards > keld thanks, keld -- Roberto Spadim Spadim Technology / SPAEmpresarial -- 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
