If the drives in a DNS-323 were formatted asRAID-1, it is possible to recover from a single hard drive failure by replacing the faulty drive and letting theDNS-323 rebuild the array.

To ensure this procedure succeeds, we recommend following the steps given below:

• power down the DNS-323 before removing the faulty drive
• do NOT turn the DNS-323 back on again until a replacement drive has been installed; this can lead to data loss under certain circumstances
• make sure the replacement drive is either new and has never been formatted, or has only been used in Windows or Mac computers using their native file systems (NTFS, FAT32, HFS ). If it has previously been formatted as part of a DNS-323RAID-1 array, this may cause rebuilding the array to fail
• install the replacement drive and power up theDNS-323
• once the DNS-323 is running, log in to the web interface. You will be prompted to format the replacement drive, and the DNS-323will restart once this is complete
• after restarting, the DNS-323 will start synchronising the disks and rebuilding the array. Depending on size and usage of the disks, this may take several hours to complete. It is possible to use theDNS-323 while this is going on, but it may further delay the process

You can check the current status of the RAID-1array on the status page; it will show either a percentage indicating how far it has progressed or Complete after it has finished.