try it, i bet that you will get better latency results with proper configured iscsitarget/initiator. btw, freebsd 10 includes kernel based iscsi-target now. which works pretty good for me since some time, easy to setup and working performing well (zfs not to forget ;) ) On Thu, Jan 9, 2014 at 9:20 AM, Markus Stockhausen <stockhausen@collogia.de>wrote:
Von: Karli Sjöberg [Karli.Sjoberg@slu.se] Gesendet: Donnerstag, 9. Januar 2014 08:48 An: squadra@gmail.com Cc: users@ovirt.org; Markus Stockhausen Betreff: Re: [Users] Experience with low cost NFS-Storage as VM-Storage?
On Thu, 2014-01-09 at 08:35 +0100, squadra wrote: Right, try multipathing with nfs :)
Yes, that´s what I meant, maybe could have been more clear about that, sorry. Multipathing (and the load-balancing it brings) is what really separates iSCSI from NFS.
What I´d be interested in knowing is at what breaking-point, not having multipathing becomes an issue. I mean, we might not have such a big VM-park, about 300-400 VMs. But so far running without multipathing using good ole' NFS and no performance issues this far. Would be good to know beforehand if we´re headed for a wall of some sorts, and about "when" we´ll hit it...
/K
If that is really a concern for the initial question about a "low cost NFS solution" LACP on the NFS filer side will mitigate the bottleneck from too many hypervisors.
My personal headache is the I/O performance of QEMU. More details here: http://lists.nongnu.org/archive/html/qemu-discuss/2013-12/msg00028.html Or to make it short: Each I/O in a VM gets a penalty of 370us. That is much more than in ESX environments.
I would be interested if this the same in ISCSI setups.
Markus
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