> > No, raid6 survives the simultaneous failure of two disks. > > Raid5 survives the simultaneous failure of one disk only. Even with a > > hot-spare, after this failure you have a time frame where the spare is > > synching and your array has no redundancy left. Thus, nearly every other > > disk failure (except a failure on the synching spare) within this time > > frame kills your array. > > > > It's worth noting that a failure mode that is getting increasingly > frequently reported is the failure of a drive *during sync*. I suspect > that the cause is that synchronization puts different stresses on the > drives than normal operation. Yes, that, and with both drives and RAID arrays growing larger, it's taking longer for arrays to re-sync, meaning a failure during any random time period is going to be more likely to fall during a sync. When I first installed a RAID system on my server, it only took a few hours to sync the 320G array. Now it can take up to 3 days to synch the 8T array. -- 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
