It can. I have seldom had need to worry about it. Most data centers have battery backups to keep power outages from crashing systems. I am also not sure if its any more or less of a risk than iscsi, except you may not be able to tell right away. async works by basically lying to the client about the read/write. Keep in mind that the read/write may be into a virtual machine in this case. Even if all packets are accounted for, not completing the full stream of writing could lead to a corrupt VM filesystem anyway. In my mind, its worth the risk for the speed. This is also why we do backups. On Fri, Mar 23, 2012 at 7:48 AM, Morgan Cox <morgancoxuk(a)gmail.com&gt; wrote: > Thank you Gary. > > After re-mounting the NFS share with async it dramatically increased the > speed ! > > I can now create a 10GB virtual disk in 2 mins (rather than 10 mins) > > Is using the async option more likely to cause data corruption though ? > > Many thanks > > Regards > > On 22 March 2012 21:54, Gary Scarborough <virtuallymad(a)gmail.com&gt; wrote: > >> >> >> On Thu, Mar 22, 2012 at 12:59 PM, Morgan Cox <morgancoxuk(a)gmail.com&gt;wrote: >> >>> Hi. >>> >>> After my many issues with spice I have finally sorted them out. >>> >>> Now I am having an issue with the speed of virtual disk creation - when >>> I go to create a virtual disk it takes a long time (far to long to >>> be usable) >>> >>> My setup is as following >>> >>> 3 servers:- >>> >>> 1 Frontend (ovirt engine) - Fedora 16 - external + local IP >>> (91.215.xxx.xx + 10.0.0.10) >>> 1 Ovirt node (using the node .iso) - external + local IP (ovirtmgmt >>> (eth0) - 91.215.xxx.xxx and LAN (eth1) - 10.0.0.101) >>> 1 NFS storage - external + local IP - I attached the storage using the >>> Local IP (10.0.0.190) >>> >>> All servers are connected via a Gigabit switch (so speed should be >>> better) >>> >>> I can scp between servers far faster - I'm almost sure its due to the >>> node ovirtmgmt address being an external (internet ip) and not LAN ip. >>> - therefore the traffic is not just going over the gigabit switch but via >>> the core router in the DC... >>> >>> Can anyone suggest how I can 'debug' where the slowness is coming from >>> >>> On my NFS server I have it setup like (in /etc/exports) >>> >>> /storage1 *(rw,sync,no_subtree_check) >>> >>> I had previous tried setting up the node on a LAN IP previously and it >>> caused spice to not work - as the node had no internet access / DNS - I >>> also tried making the frontend server a gateway (and using - iptables -t >>> nat -A POSTROUTING -j MASQUERADE ) - this also cause spice to not work (as >>> it always tried to connect to the 10.0.0.x address from my desktop - and >>> fail..) >>> >>> Any hints/help will be welcomed >>> >>> Cheers >>> >>> >>> >>> _______________________________________________ >>> Users mailing list >>> Users(a)ovirt.org >>> http://lists.ovirt.org/mailman/listinfo/users >>> >>> >> You could try async instead of sync. You could also try thin >> provisioning. >> >> -- >> Gary Scarborough >> IST Lab Manager >> Rochester Institute of Technology >> Rochester NY >> > > -- Gary Scarborough IST Lab Manager Rochester Institute of Technology Rochester NY