SATA virtual hard disks: still experimental?

[SvenGus]

Being that if one creates a new VM, it still defaults to SCSI...: is SATA still at an experimental level, or is it really the recommended way (as someone said elsewhere, here, IIRC) of choosing the virtual HD?

But the latter seems unlikely, if it isn't selected automatically when you create a new VM...

So, still not at the level of Parallels and VirtualBox, for virtual SATA support?

Just out of curiosity: it looks like a good option - but is it really optimal, presently...?

[dariusd]

Hi Sven,

The default reflects a recommendation and is based upon the guest OS you select.  For some guest OSes, we recommend virtual SATA HDD and/or CD so we create those by default, and for others we still recommend SCSI or even IDE.  Our recommendation is driven by the expected level of supportability of the guest OS on each of the available controllers.  (Some guests have defective drivers for some controllers, or have slow drivers, or simply lack the needed drivers...)

The virtual SATA implementation in Fusion 6 (and Workstation 10) has been very thoroughly tested and is certainly not experimental.

That said, please do let us know if you encounter any problems with it! 

Cheers,

--

Darius

[SvenGus]

Thank you, Darius: very interesting...

Personally, I have tried creating new Windows 7, Windows 8, Ubuntu and OS X VMs, just to see how they defaulted for the virtual HDs: well, Windows 7 and 8 defaulted to SCSI for the HD and SATA for the CD/DVD, the same for Ubuntu, while OS X 10.7/10.8/10.9 had SATA for both.

BTW, previously, I had converted two existing OS X (10.7 and 10.8) VMs to SATA, and, IIRC (at least in the 10.8 one), the converted SATA HD appeared as an external one (in orange): maybe that - well, rather more cosmetic than substantial - issue should be addressed, in a future update...

But the most important question probably is: is a SATA virtual HD recommended for Windows 7/8/8.1 and Ubuntu - or is it better to remain with SCSI...?

Well, let's try and see (SATA, anyway, looks more "(post)modern", so to speak)...

[dariusd · Accepted solution]

I'd say that the recommended HD is probably what Fusion gives you.  :smileygrin:

But... modern OSes (certainly Win7 and Ubuntu) should be fine with SATA for virtual HD and CD/DVD.

To explain further: Our recommendations can and do change over time, across products and versions, and sometimes the reason is not obvious – as one example, many users might want to move a VM from the latest Fusion or WS release to an older ESXi release, and we try to avoid having our defaults get in the way of that (as long as the version disparity is not too great), so we might not immediately recommend the best available storage controller for a particular OS in the first release that the controller is supported.

The recommendations also change according to our understanding of the state of the art and the future of physical hardware and guest OSes.  All physical Macs have had SATA HDD and DVD for years now, for instance; Now that Fusion has a virtual SATA controller compatible with the AHCI driver in OS X, there's a compelling case to recommend SATA for OS X guests, even at the expense of the aforementioned backward compatibility, since we have a higher degree of confidence that the OS will continue to support AHCI for the foreseeable future.  Windows and Linux distros tend to be exposed to a wider variety of (physical) hardware, and have a massive installed base with wide driver support and less likelihood of storage controllers being deprecated, so backward compatibility and proven history are more compelling reasons to keep the status quo.

TL;DR: The default is a generic recommendation, driven by lots of conflicting factors.  Adjust to suit your particular needs.  Let us know if you think the recommendation is egregiously wrong.

Cheers,

--

Darius

[SvenGus]

Excellent explanation.

BTW, I just installed Windows 8.1 RTM from TechNet with a SATA virtual HD, and indeed it seems to work OK...

... And it's also quite fast, much faster (at least as a first impression) than previous Windows versions in Fusion: don't know, however, if it's because of the virtual SATA bus, and/or Fusion 6 improvements, and/or Windows 8.1 RTM itself - maybe/probably all together.

And it also looks like there's no more "Windows Update Cleanup" in cleanmgr.exe (which anyway is still quite slow...), which previously took almost an eternity (in the order of tens of minutes; and also in Parallels: must be some VM thing, in general)...

[SvenGus]

... OK, so I successfully converted all my VMs to SATA, except for the Windows 7 Pro one, which bluescreens when booting (after the animated Windows logo), thus triggering the troubleshooting tool (or whatever it's called...), which sadly solves nothing: same blue screen at the next reboot.

So, it looks like an existing Windows 7 VM cannot be converted from SCSI to SATA (both HD and CD/DVD)...?

Well, anyway, I can always recreate the VM ex novo, when I have some time - no problem...

[SvenGus]

Problem solved; I restored the Windows 7 VM from a backup, and then followed the procedure outlined here:

FUsion 6 and SATA Equals Blue Screen

... thus, after shutting down the VM, beginning with changing only the virtual CD/DVD from IDE to SATA, which installs a SATA controller and drivers in Windows 7; and only subsequently, after shutting down the VM again, changing also the virtual HD from SCSI to SATA: after booting, Windows 7 installs the virtual SATA HD device, and now everything works (after a reboot and a Windows reactivation, of course)... :smileycool:

[SvenGus]

BTW, for OS X guests converted to SATA, be sure to select the startup disk in the *Fusion VM settings*, as the startup disk selected inside the OS X System Preferences doesn't seem to stick across reboots; otherwise, it will first attempt to start up from "EFI network", which adds some seconds to the total boot time.

Still a mystery why the SATA HD appears as "extractable" (with orange icon) in 10.8, while it is an ordinary internal disk (with grey icon, as it should be, and as it was with SCSI) in 10.7...

[dariusd]

Right, converting an EFI-based VM (such as OS X) to SATA will currently trigger an unfortunate problem with the EFI device boot order.  I wouldn't advise changing the disk type of any boot disk for an installed OS... it'll be very difficult to predict the outcome.  Windows will generally BSOD, Mac OS might encounter boot order problems, EFI-based Linux VMs (only supported on ESXi) may be rendered unbootable, ...

The problem with the guest's Startup Disk preferences probably has the same root cause as the SATA + FileVault 2 problem reported earlier in another thread.  I'll continue to investigate that.

Hmmm... I thought we'd fixed the "extractable" issue... Is the VM's guest OS type set to the correct version of OS X (in VM > Settings > General)?

Cheers,

--

Darius

[SvenGus]

Yes, of course one shouldn't make similar experiments with production VMs; anyway, one should always keep full backups of the VMs!

... My OS X 10.8.5 VM is of the correct type; I temporarily switched its language to English, so here are also the correct terms for the virtual HD in System Information:

Removable Media: Yes

Detachable Drive: No

I also noticed that it identifies the drive as being an SSD: which is correct, too, because I have all the VMs on an Optibay SSD in the former SuperDrive bay on my MacBook Pro (and the main boot drive is also an SSD, of the same type); BTW, should I enable TRIM also inside the VM, or is it enough to have it enabled in the host?

IIRC, it should probably be enough to have TRIM enabled only on the Mac side (also as the VMs are simply files for the host system) - but just to be sure...

[SvenGus]

... BTW, should one want to easily access the BIOS/EFI of a VM, here are the official instructions (from the Fusion 6 release notes):

• Accessing the BIOS or EFI in a virtual machine is now much easier. Under Settings > Startup Disk, hold the Alt/Option key and select Restart to firmware.

But that shouldn't be necessary, here... or are there some options that should be tweaked, after converting a VM to SATA?

Thanks for any help...

P.S. (nothing to do with VMs): This forum has some issues with the iPad: drop-down menus and reply links don't seem to work, with it (but that's perhaps some Safari for iOS issue, who knows?)... :smileyinfo:

[dariusd]

In certain configurations, we pass through host SSD-ness to the guest, which helps the guest OS with correctly optimizing its disk access patterns and disk maintenance methods for the media type.

You're right about TRIM.  It might be helpful on the host side, but not within the guest for a VM running on Fusion.

Our virtual SATA controller does support hot-plug, so the drives should be hot-removable.  We had to disable SATA hot-plug for 10.7 and earlier due to a guest OS defect, but for 10.8 and newer it should be active.  It's interesting that the OS reports that the media is removable but the drive is not... it should be the other way around.

Cheers,

--

Darius

[SvenGus]

BTW, here's a screenshot of the OS X 10.8 VM (converted from SCSI to SATA):

... where one can directly see the relevant information.

[WoodyZ]

If you want to have the icon currently showing for OSX on the Desktop be that of a normal internal drive then in a Termnal:

open /System/Library/Extensions/IOStorageFamily.kext/Contents/Resources/Internal.icns

This should open it in Preview, then Command+C to copy...

Select OSX icon on the Desktop and press Command+I to bring up Info and select the icon in top left corner of the Info sheet and press Command+V.

Now it should look like a normal internal drive.

[SvenGus]

Thanks for the tip! :smileycool:

[thejapanese]

Hi,

does it give a "speed bump" if I would run a guest machine hard disk in SATA mode instead of SCSI?

I'm using 10.9 / Fusion 6.01 and a Win 7 x64 guest.

[gringley]

I have converted all but my Windows XP guests to SATA and things seem OK.  Seems like a good idea to go with the current and future rather than a past you can't buy anymore?

[dariusd]

Hi Sven G,

Just a quick note to let you know that Fusion 6.0.2, released just a few hours ago, addresses the problem you reported with SATA HDDs and the in-guest controls for selecting the startup disk.  Once you upgrade to Fusion 6.0.2, you should be able to deactivate Fusion's boot device override (Virtual Machine > Settings, choose Startup Disk, and choose Restore Defaults) and then you should be able to use the guest's System Preferences > Startup Disk to choose the startup device.

Thanks for reporting the issue!

Cheers,

--

Darius