November 27, 2022 at 12:46 PM, "Reindl Harald" <h.reindl@xxxxxxxxxxxxx> wrote: > > Am 26.11.22 um 21:02 schrieb John Stoffel: > > > > > I call it a failure of the layering model. If you want RAID, use MD. > > If you want logical volumes, then put LVM on top. Then put > > filesystems into logical volumes. > > So much simpler... > > > > have you ever replaced a 6 TB drive and waited for the resync of mdadm in the hope in all that hours no other drive goes down? > > when your array is 10% used it's braindead > when your array is new and empty it's braindead > > ZFS/BTRFS don't neeed to mirror/restore 90% nulls > You cannot consider the amount of data in the array as parameter for reliability. If the array is 99% full, MD or ZFS/BTRFS have same behaviour, in terms of reliability. If the array is 0% full, as well. The only advantage is you wait less, if less data is present (for ZFS/BTRFS). Because the day that the ZFS/BTRFS is 99% full, you got a resync and a failure you have also double damage: lost array and 99% of the data. Furthermore, non-layered systems, like those two, tend to have dependent failures, in terms of software bugs. Layered systems have more isolation, bug propagation is less likely. Meaning that the risk of a software bug is much higher, to happen and to have catastrophic effects, for non-layered systems. bye, pg -- piergiorgio sartor
