Thanks for the helpful response. FYI, I did some more research and discovered that Hyper-V doesn’t support booting from virtual SCSI drives, so that solves that.
I have another vm running on my laptop under KVM that runs substantially faster than the hyper-v vm. My laptop is far below the hyper-v server in most respects performance-wise, but it does have an SSD. I’d be curious to find out how much of that is raw disk IO performance and how much is KVM vs Hyper-V and openbsd’s respective drivers for each. I’ll give the softdeps suggestion a shot. Sent from my iPhone > On Oct 23, 2017, at 7:25 PM, Nick Holland <n...@holland-consulting.net> wrote: > >> On 10/23/17 17:41, Daniel Boyd wrote: >> Is there a recommended configuration for virtual disks in Hyper-V? I >> have a virtual machine that I set up recently running 6.2 that has >> *very* slow disk performance. It took well over an hour to untar >> ports.tar.gz. The host server is a few years old, but it's running 3 >> RAID-5 7200rpm drives, quad-core Xeon and 32 GB RAM... so not exactly a >> slow machine. And this is the only Hyper-V VM it's hosting. > > actually...raid5 is slow on writes (write one block = read existing > block. Read parity block. Write data, write parity. Hopefully, you > have a write cache that's on and working), 7200rpm drives are slow by > any standards these days. That's a heavy-lifting drive, not anything to > mention in the same sentence as "not slow". > > (don't get me wrong, I got a lot of heavy-lifting drives. And I'm kinda > slow. But I try to be realistic about it). > >> I've got the virtual disk configured as IDE / VHDX / Expanding (the >> Hyper-V defaults). > > "expanding" means not preallocating the disk, I'm guessing? Again, not > a performance choice. Your file system fragments are going to be > fragmented. > >> The controller can be IDE or SCSI. The disk format >> can be VHD or VHDX. And the disk can be configured as fixed or >> expanding. I'm going to try converting the disk to fixed and >> defragging my NTFS. >> >> Any thoughts on IDE vs SCSI and VHD vs VHDX? > > Neat thing: OpenBSD doesn't care much. You can change it at the > hypervisor level, reboot, and see for yourself how it works. This isn't > Windows or Linux which will have a cow if you change the disk type or > controller type after load. (before DUIDs, you might have to change your > /etc/fstab, but as long as you are using DUIDs, you should be in good > shape there). > > But ... for unpacking ports, make sure that file system is mounted (at > the OpenBSD level) with softdeps. Yes, it's really a huge difference > for lots of tiny files, which is exactly what the ports tree is. This > will matter more than hypervisor knobs, I suspect. > > Nick. >
