Not true 哦

From DLINK DNS343 support page

How do I restore RAID1 or RAID5 on my DNS-343 Series ShareCenter if a drive has failed?
A Note: If a drive has failed, the DNS-343 Series ShareCenter LED will display the corresponding drive as missing and you will receive an email from the DNS-343 stating a drive has failed if this option has been configured

If this happens, follow these steps to restore the RAID1 or RAID5 settings:

Step 1: Power down the ShareCenter

Step 2: Remove the failed drive from the ShareCenter

Step 3: Insert the new drive into the ShareCenter

Note: The new drive Should be blank with no partition on the drive The drive may still be detected and prompt to format if formatted incorrectly

Step 4: Power on the ShareCenter

Step 5: After a minute log into the ShareCenter web interface

Step 6: You will be prompt to format and re-sync on entry, click OK

Note: Formatting a hard drive will erase the data stored on the hard drive. Please backup important data before formatting a hard drive

Note: This action will format the replaced drive only and sync remaining RAID drives

Step 7: The ShareCenter is now ready for use. You can continue to use your ShareCenter while your newly inserted harddrive is being synced.