[Still waiting for answers on my earlier questions]
So I take it that ZFS solves one problem perfectly well: Integrity of data blocks. It uses CRC and atomic writes for this purpose, and as far as I could follow this list, nobody has ever had any problems in this respect. However, it also - at least to me - looks like that there is a chance that you have a disk in your hands with 100% correct data blocks, but no way to retrieve a single one; under the unfortunate circumstances that the semantics of these blocks is lost. From what I can gather here, and correct me if I am wrong, the problem is not so much on the individual file system to which these 100% correct blocks belong, than on the level of the overall structure of those filesystems. If this was the case, a copy/mirror like it is used in FAT32 might be one solution, though maybe not the most elegant one. Could another approach be, to provide each file system a (virtual) self-contained, basic, pool to which it belongs, and from that it could be recovered? A pool that is over-ruled by the existence of a consistent higher-level pool (the one that the user has created and the user interacts with)? I concede that these might be impossible one way or another, but conceptually at least, a fall-back pool is thinkable. Nobody expects consistency of a file that sees the drive yanked while the writing is going on. But an 'atomic' update before and after could be useful; one that propagates through to the upper level, so that the state of the pool is consistent at any moment, with or without the changes of the underlying file system. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
