On Thu, Dec 10, 2009 at 06:17:24PM -0500, nixlists wrote: > On Thu, Dec 10, 2009 at 6:00 PM, Marco Peereboom <[email protected]> wrote: > >> Does this mean there's little advantage of hardware mirror raid over > software? > >> So software mirror raid increases chances of data corruption while > decreasing > >> the chances of downtime. True for hardware as well? > > > > There are pro and cons to both solutions. Pick what makes sense in your > > scenario. > > > >> Hmmm. I've used hardware raid cards for mirrors that have the verify > function. > >> It would be interesting to know how and what those cards do. > > > > They read the data to make sure the disk is working. If one disk is > > failed they can rebuild that block from the remaining disk provided that > > the remaining disk isn't corrupt or broken too. They assume that the > > data that was read is accurate; if it isn't you are SOL. > > > > They either don't detect or ignore blocks that are different because > > they can not know which one is accurate (if any). > > > > Verify for RAID 1 is mostly marketing fluff. > > Thanks a lot for this info. In the past I've had weird corruption of > files with a > raid card - some files on the volume would become corrupt, but the > corruption was limited > to files only. IOW the whole volume would be intact and I could write > and read new files to it > but as the time went some individual files would contain garbage > instead of real data. I wonder > what that was all about.
probably a crappy card or disks.
