When a device is added to raid array, the data on that device will not be synchronized with the other devices. The kernel begins to scan the original devices and writes the correct blocks to the new device. This process is known as resyncing.
This resync process details can be viewed from the
/proc/mdstat and
syslog files.
There are times when you may want to control how much I/O bandwidth is allocated to the resync and this is done by writing values to
/proc/sys/dev/raid/speed_limit_max
/proc/sys/dev/raid/speed_limit_minYou can set or limit minimum or maximum speed of RAID reconstruction in these files.
Hope the above information would help you.
