Set new max values to help speed up the RAID operation
$ echo 32768 > /sys/block/md2/md/stripe_cache_size # This is the max value, and it takes up 32Mib to synchronize read/write operations while the array is degraded
$ echo 50000 > /proc/sys/dev/raid/speed_limit_min # This is a hint that you want more focus on the sync-expansion task
$ echo 32768 > /sys/block/md2/queue/read_ahead_kb # This is how far ahead of a read request the drive array will preload
$ echo max > /sys/block/md2/md/sync_max
After RAID operation completes have a command to set the values back to the default captured in step 1.
Details on how much faster the RAID operation was by setting the different values in this gist comment.
Providing the ability to speed up RAID Resyncs and Reshaping would be very helpful. This gist has alot of details on it.
Details on how much faster the RAID operation was by setting the different values in this gist comment.