Increase Performance with mdadm variables

Hi All,

I'm hotly anticipating delivery of my ReadyNas 314 unit and also reading about the risks associated with high RAID5 rebuilt times when using multi-TB drives and arrays.

I was wondering if it's possible to apply some different values to the system in order to speed up array rebuild/resync, as outlined in this article, albeit for another brand of device:

# echo 100000 > /proc/sys/dev/raid/speed_limit_min # echo 32768 > /sys/block/md3/md/stripe_cache_size The first command increases the minimum “goal” rebuild speeds for when there’s non-rebuild activity. On my DS414 I never saw this go above 90000KiB. The second command increases the stripe cache size which increases sync performance by allowing a larger cache to synchronise the read and write operations on the array. This is only available for RAID 5 volumes and it does decrease the amount of available system RAM but I never saw 100% utilisation on the DS414."

http://www.richardglover.co.uk/2014/04/speeding-up-raid-migration-on-a-synology-ds414-nas/

I do realise that RAID is not backup and I have that sorted out but it would be great to be able to have rebuilds happen in the shortest possible time.

Thanks.