Bob wrote: > ... Given the many hardware safeguards against single (and several) bit > errors, > the most common data error will be large. For example, the disk drive may > return data from the wrong sector.
- actually data integrity check bits as may exist within memory systems and/or communication channels are rarely prorogated beyond their boundaries, thereby data is subject to corruption at every such interface traversal, including for example during the simple process of being read and re-written by the CPUs anywhere within the system that touches data, including within the disk drive itself. (unless a machine with error detecting/correcting memory is itself detecting uncorrectable 2-bit errors, which should kill the process being run, there's no real reason to suspect that 3 or more bit errors are sneeking through with any measurable frequency; although possible). - personally I believe that errors such as erroneous sectors being written or read are themselves most likely due to single bit errors propagating into critical things like sector addresses calculations and thereby ultimately expressing themselves as large obvious errors, although actually caused by more subtle ones. Shy extremely noisy hardware and/or literal hard failure, most errors will most likely always be expressed as 1 bit out of some very large N number of bits. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
