RAID1 Resyncing – Can Files Be Written Immediately?

btrfscentoshard drivemdadmraid1

I searched but i just found this.

How to interrupt software raid resync?

My question is

can i write files to my raid1 device while…

[root@centos ~]# cat /proc/mdstat
Personalities : [raid1] 
md0 : active raid1 sdb[1] sda[0]
      3906886464 blocks super 1.2 [2/2] [UU]
      [====>................]  resync = 24.2% (946291392/3906886464) finish=426.0min speed=115826K/sec
      bitmap: 24/30 pages [96KB], 65536KB chunk

unused devices: [none]

Will it makes my hard drives own different data?

Then if i manually start a resync process,

Will my datas be covered?

And how to manually start a resync process?

I searched "What does resync mean" and websites are all just shown "sync the data between device a and device b".

Ok back to the main topic,
If I just created a RAID1 device,
and it is resyncing,
can i write files to it immediately?

Best Answer

You can use your RAID array immediately, but writes may be slower while the resync is in progress. The resync will pause while your disk writes occur, and then resume when you are not writing to the disk.

Because you created a RAID 1, it is necessary that both disks contain exactly the same data, in order to be consistent. Thus the data from one drive is copied to the other during the resync. This is done when you first create the RAID array, and it is also done when you replace a (bad) disk. The resync can be interrupted by powering off the machine, but the resync will continue when it is next rebooted.

Related Topic