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.
