On Sun, Nov 27, 2022 at 07:21:16PM +0100, Reindl Harald wrote: > > > Am 27.11.22 um 15:10 schrieb piergiorgio.sartor@xxxxxxxx: > > 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 > > you completly miss the point! > > if your mdadm-array is built with 6 TB drivres wehn you replace a drive you > need to sync 6 TB no matter if 10 MB or 5 TB are actually used I'm not missing the point, you're not understanding the consequences of your way of thinking. If the ZFS/BTRFS is 99% full, how much time will it need to be synched? The same (more or less) of MD. So, what's the difference in *this* case? None. This means the risk of (you wrote, I believe) an other disk to go down is the same. This means that you're considering the reliability as function of how much the array is full (or empty). No matter if MD takes *always* full time. It's not the point, in relation to reliability. In other word, ZFS/BTRFS optimize the sync time, for sure, but this should *not* be considered when thinking in terms of reliability. bye, -- piergiorgio
