Data checksums

IBM Storage Scale RAID stores checksums of the data and redundancy information on all disks for each vdisk. Whenever data is read from disk or received from an NSD client, checksums are verified. If the checksum verification on a data transfer to or from an NSD client fails, the data is retransmitted. If the checksum verification fails for data read from disk, the error is treated similarly to a media error:

• The data is reconstructed from redundant data on other disks.
• The data on disk is rewritten with reconstructed good data.
• The disk badness is adjusted to reflect the silent read error.