On Mar 9, 2011, at 2:37 PM, Chris Murphy wrote: > > >> 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....
Because the Raid 5 and Raid 6 volumes are mirrored together using ZFS, ZFS will catch any "silent" corruption since the Raid 5 and Raid 6 volumes still are being managed by ZFS in a mirror and ZFS can do its thing with regard to data integrity. Why do it that way? Large part of it was related to the HW I had on hand and an existing RAID 6 volume sitting by itself with ZFS as the base etc. > > > Chris Murphy _______________________________________________ MacOSX-admin mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-admin
