Well, this is really strange! For unmounting a volume, I need to restart?!
At the moment I have no problem with this, as we are still in testing state!
But when we will start production state, we will have some VMs running on iSCSI, so restarting will not be so easy... I thought about using a Dynamic Volume for offline backup to an external hard disk... :-(
My setup was more aggressive and I just pulled the USB cable from the system and did a rescan. I was not aware of this until now that you tell me so hard for me to know this without some background from you on your setup. If this is the case then test the immediate dismount live from the system and do a rescan as I did.
I already thought about the possibility "just pulling USB" of course, but I didn't dare... Couldn't you simply add an unmount button in the next release?
I just created the 5 GB iSCSI volume and formatted it via WAN. Now I have 4 GB "reserved for system" and only 0,9 GB free. I started a backup to my dynamic volume but it failed with error 23: Not enough space for backup volume available.
How can I get rid of these 4 GB space "reserved for system" to use it for the backup database.
You cant as it is needed for other resources for the DSS V6, try taking from the SWAP, just delete then give 2GB back to the SWAP and the rest you can add to the LV.