[pve-devel] [PATCH V3 pve-storage] lvm: use blkdiscard instead cstream to saferemove drive

[Fiona Ebner]

Am 20.10.25 um 4:37 PM schrieb DERUMIER, Alexandre:
>>
>> "There are no restrictions when using blkdiscard -z, although
>> blkdiscard performs roughly the same as dd if the storage does not
>> support write same."
> 
>>> At a glance, the implementation of blkdiscard doesn't seem to have a
>>> fallback and will just exit with error if the BLKZEROOUT ioctl()
>>> fails:
>>> https://github.com/util-linux/util-linux/blob/stable/v2.41/sys-
>>> utils/blkdiscard.c#L303
> 
> Thanks to have looked at it!
> 
> So I'll readd the cstream as fallback to be sure && keep
> saferemove_throughput too ?

Even if the kernel does have a fallback (see my other mail), this is the
safe way to go about it, since the kernel will just write zeroes full
speed. Otherwise, we risk breaking somebody's setup. We can think about
dropping it for PVE 10.