On Mar 9, 2011, at 2:27 PM, objectwerks inc wrote: > > > A power failure or sudden crash is not the only place corruption can enter.
Of course not. Those are much more likely to qualify as silent. I do not consider a kernel panic or power failure to be silent events. They're quite "loud" sources of data corruption. Not unique to RAID 5.. > But on the Time Machine side, if you want a more reliable time machine backup > solution, build or buy a box running Nexenta that uses ZFS and then create > AFS services on it that you can target your Time Machine to. I am in the > process of implementing this in my office. Practically anything but a Microsoft FS would be more reliable than Time Machine backups on jhfs+ on a single drive. But yes I agree with your strategy. Nevertheless, silent data corruption should have a specific meaning and I do not take it to mean ordinary corruption we expect to get from kernel panics and power supply failures, and that's MOST of what your cited articles are talking about with respect to RAID 5. Well, yeah that's an airplane landing into Baghdad at the height of the Iraq war. That has nothing to do with the incidence of silent data corruption. > My hosting business actually also uses Nexenta and has two HW RAID Cards > (Areca with battery back NVRAM). One HW Raid is a Raid 6 and one a Raid 5 > using bigger base disks. Then I use these two volumes in a ZFS mirror, along > with a mirrored SSD ZIL. The server sits in a UPS and generator backed data > center as well. Provides good performance and I should be able to tolerate a > lot of disks going out at once. Why not just RAID-Z? If you're going to complain about RAID 5 having a greater instance of parity related problems, it would seem like using RAID 5 as a base very well will mean it can get corrupted and ZFS won't be able to do anything about it at all except repair what's in its own domain - which is not the base RAID 5 parity data.... Chris Murphy_______________________________________________ MacOSX-admin mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-admin
