Re: linux dom0 versus NetBSD dom0

[Roger Pau Monné <roger.pau%entel.upc.edu@localhost>]

2012/1/11 Greg Troxel <gdt%ir.bbn.com@localhost>:
>
>  1.  Does anyone have i/o bench marks comparing network and disk throughput
>  when using Linux versus NetBSD as Dom0?
>
> I don't have any real benchmarks, but with NetBSD as dom0 and domU I've
> observed < 10% loss in dd rate of xbd0d compared to dd from the file in
> the dom0, and another < 10% loss from dd from that file compared to dd
> From the raw disk.
>
>  2.  We know we can use the xbd driver
>  to provide virtual disks in NetBSD, but are other storage technologies
>  mature in the NetBSD environment?  I'm thinking aboutthings like ISCSI,
>  NFS, or other network storage technologies.
>
> I use files in the domU filesystem (RAID1 raidframe on local sata), and
> that has been both satisfactory and solid.  Using NFS seems scary (not
> about NetBSD - just putting NFS in the path from an OS to what it thinks
> is a disk).
>
> My understanding is that as long as you have block device (including
> vnd) to hand to xen, all is well.  So vnd of a file in NFS should work,

Trying to attach a vnd of a file in NFS makes the NetBSD Dom0 kernel
crash, as described here:

http://gnats.netbsd.org/40726

> and vnd of a file in iscsi, or an iscsi block device should also work.
> I would suggest that setting it up to try with your storage setup should
> be pretty easy.
>
> One thing that has been trouble in the past and may still be trouble is
> vnd with sparse files.
>
>  0. [missing question about reliability]
>
> My group has had 3-4 xen boxes, each with NetBSD dom0, with the oldest
> going back to 2005.  It's been highly reliable, with the dom0 typically
> being up for on the order of a year until we have grid power issues.
> There have been crashes, but less than 1/year/dom0.