[pve-devel] scsi-hd vs scsi-generic with iSCSI

[Thomas Lamprecht]

On 9/29/19 5:01 PM, Daniel Berteaud wrote:
> ----- Le 28 Sep 19, à 9:38, Dietmar Maurer dietmar at proxmox.com a écrit :
> 
>> What exactly is the problem with scsi-generic? Maybe we can fix it?
> The two main issues I have are :
> 
>   * Bug #2380 : if we try to move a disk from a ZFS over iSCSI storage of a running VM, I/O errors will be reported to the guest, and its FS will "panic". When a drive mirror is running, any reads (probably writes too) will fail with I/O error
>   * Bug #2335 : when resizing a disk, the guest is not notified about the new size, you have to rescan the SCSI device for the new size to be visible
> 
> If switching to scsi-hd instead of scsi-generic, then both of those issues are gone. Drive mirror and resizing works like for any other storage types (which, for most of them, also use scsi-hd)

But the interesting thing would be, why is there an issue with scsi-generic,
i.e., the underlying issue for the two Bugs. IIUC, Dietmar had in mind to
try to fix those - and thus help all scsi-generic users, instead of working
around the issue.

The initial question would be: what does the scsi-hd type differently.
(maybe hard to tell if they're both complete different implementations)

cheers,
Thomas