[pve-devel] adding libiscsi to qemu-kvm ?

[Dietmar Maurer]

> >>For me this is a step back.
> I disagree.This is a huge step for direct iscsi luns.
> I can tell you that it's currently a pain to manage with a lot of luns.

Yes, that is why most people use LVM on top of iscsi. 

Note: Simple ignore my ignorant comments ;-) I know that this does not help you. 

> >>We lose snapshot capabilities and multipath support?
> 
> which snapshot capabilities ? I'm talking about iscsi devices, not lvm on top
> of iscsi.

Ah, OK.

> Snapshots/cloning must be done on the san side. (nexenta,netapp,.. have api
> to do this).
> About multipath, I can tell you that with 500luns, it's pretty impossible to
> manage. (it's using a lot of cpu and hanging sometimes) In fact,i'm going to
> implemenent lacp soon, I have add too much problem with multipath
> daemon.
> 
> 
> Currently if something goes wrong (failover of san controller or network
> saturation), with a lot of luns, kernel take a lot of time to restore device
> access.
> last time, I have a 30sec failover, kernel+multipath have take 5min to restore
> device access...
> With libscsi, it take around 5sec to restore access.
> >> And as soon an ceph/sheepdog is stable you will dump iscsi anyways?
> 
> Sure, but I don't want to put to trash a 100.000$ san, right ? ;) 

Ok, please send the patch. Adding another storage plugin does not harm -
I guess it is just a few lines of code?

- Dietmar