On 17/04/13 14:27, Robert L Mathews wrote: > But complete disk death doesn't seem to be the normal failure mode. If > the failure is spurious, as so many seem to be, and temporarily > affects an array so that each disk has a different event count, that > isn't a disaster under RAID 1. If worst comes to worst, you can pick > one disk to use and pretend RAID doesn't even exist. You don't need to > get the members to successfully sync into an array to read the data. > But if each disk in a RAID 5 or RAID 6 array gets a different event > count, or if the disks refuse to easily assemble into an active array > for any other reason, all your data is inaccessible until you fix the > RAID problem. I avidly read the details of every RAID 5 [and 6] > disaster on the list, and almost every one would be trivially easy to > fix under RAID 1, with no risk of complete data loss. It's heartbreaking. RAID1 of course fails the requirement of a single filesystem that requires more space than a single disk can provide. Of course, you can then consider LVM2, multiple mount points, or RAID10 or RAID1 + linear etc.... but most people still prefer to see a single block device. Dealing with multiple RAID1 and a linear could lead to more complex issues as well. In any case, as mentioned previously, the majority of issues are caused by mis-configuration, if we could add some configuration verification to mdadm or similar, then we might be able to warn more people prior to things failing. Regards, Adam -- Adam Goryachev Website Managers www.websitemanagers.com.au -- 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
