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

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

• power down the DNS-323 before removing the faultydrive
• do NOT turn the DNS-323 back on again until areplacement drive has been installed; this can lead to data lossunder certain circumstances
• make sure the replacement drive is either new and has neverbeen formatted, or has only been used in Windows or Mac computersusing their native filesystems (NTFS, FAT32, HFS ). If it haspreviously been formatted as part of a DNS-323RAID-1 array, this may cause rebuilding the arrayto fail
• install the replacement drive and power up theDNS-323
• once the DNS-323 is running, log in to the web interface. Youwill be prompted to format the replacement drive, and the DNS-323will restart once this is complete
• after restarting, the DNS-323 will start syncronising the disksand 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 theprocess

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