I've googled endlessly about the internal nature of a md Raid-1. Over the years, I've found several single bit flips on traditional platter disks on files that were previously on a linux raid-1 that had split and while doing a verification of the two copies. This seems to imply that what I'm looking for doesn't exist- and that is simply a vertical parity within each disk at the md level- even a single crc32 every once in a while so that if a bit flips on drive 1 of a mirror, drive 2's copy replaces it instead of 1's bit flipped copy replacing drive 2's good copy. From what I can gather, it seems to be a 50/50 shot whether your good copy gets mangled in the event of a silent bit flippage. So- is there any built in parity that helps mdadm decide which copy to use when the copies disagree on a raid 1 mirror during a resync? If not- is there a reason why not beyond the extra space overhead and read compute write overhead? This issue interests me more as I look into SSDs and having flash blocks wear out. I'd choose a higher raid level if i could, but this is only a very small atom 330 box with only mildly important data. I think I'm ultimately looking for something like ZFS has, but ZFS under RHEL/CentOS will probably never happen in any meaningful production worthy way due licensing and the ultimate demise of sun and tainting of things that is Oracle. I'd love any information anyone has on the subject. -Brett -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
