Am 27.11.22 um 15:33 schrieb Wol:
On 27/11/2022 12:06, Reindl Harald wrote:
Am 27.11.22 um 12:52 schrieb Wols Lists:
On 27/11/2022 11:46, Reindl Harald 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
This is why you have trim.
besides that such large disks are typically HDD trim has nothing to do
with the fact that after a drive replacement linux raid knows
*nothing* about trim and does a full resync
you are long enough on this list that you should know that
Except (1) I didn't say *H*D*D* trim, and (2) if raid just passes trim
through to the layer below, THAT'S NOT SUPPORTING TRIM. As far as I'm
concerned, what happens at the level below is just not relevant!
reality don't bother what concerns you
If raid supports trim, that means it intercepts the trim commands, and
uses it to keep track of what's being used by the layer above.
In other words, if the filesystem is only using 10% of the disk,
supporting trim means that raid knows which 10% is being used and only
bothers syncing that!
this is nonsense and don't reflect reality
the only thing trim does is tell the underlying device which blocks can
be used for wear-leveling
