On Sat, 13 Jul 2013 06:34:19 -0400 "Justin Piszcz" <jpiszcz@xxxxxxxxxxxxxxx> wrote: > Hello, > > Running 3.10 and I see the following for an md-raid1 of two SSDs: > > Checking /sys/block/md1/queue: > add_random: 0 > discard_granularity: 512 > discard_max_bytes: 2147450880 > discard_zeroes_data: 0 > hw_sector_size: 512 > iostats: 0 > logical_block_size: 512 > max_hw_sectors_kb: 32767 > max_integrity_segments: 0 > max_sectors_kb: 512 > max_segment_size: 65536 > max_segments: 168 > minimum_io_size: 512 > nomerges: 0 > nr_requests: 128 > optimal_io_size: 0 > physical_block_size: 512 > read_ahead_kb: 8192 > rotational: 1 > rq_affinity: 0 > scheduler: none > write_same_max_bytes: 0 > > What should be seen: > rotational: 0 What has "rotational" got to do with "supports discard"? There may be some correlation, but it isn't causal. > And possibly: > discard_zeroes_data: 1 This should be set as the 'or' of the same value from component devices. And does not enable or disable the use of discard. I don't think that "does this device support discard" appears in sysfs. I believe trim does work on md/raid1 if the underlying devices all support it. NeilBrown > > Can anyone confirm if there is a workaround to allow TRIM when using > md-raid1? > > Some related discussion here: > http://us.generation-nt.com/answer/md-rotational-attribute-help-206571222.ht > ml > http://www.progtown.com/topic343938-ssd-strange-itself-conducts.html > > > Justin. > > > -- > 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
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