Can I switch "write-through" policy when changing content?

[mattad]

When I start a VM then a part of the VM is read from the *.vmdk into physical memory.

Then lets assume I change something or write a new text file.

The new content is (as far as I know) written immediately not only to memory but also ("Write-through") to hard disc *.vmdk.

Sometimes I prefer to have as much speed as possible. So writing to hard disc is unwanted.

Can I disable write-through resp chnage it to "write changed content to hard disc when idle" or even to "write changed content to hard disc when shutdown guestOS" ?

Solution for WS and Player preferred

Matt

[continuum]

Hi

discussing your question makes no sense without knowing your host OS and your config.ini settings.

Please add that info.

Also do you configure the mainmem parameters ?




_________________________

VMX-parameters- WS FAQ -[ MOAcd|http://sanbarrow.com/moa241.html] - VMDK-Handbook

[mattad]

My guestOS is OpenSolaris (resp. in another case Ubuntu)

My hostOS is Win7 Pro

Which config.ini do you mean? Where do I find this?

I am currently using VmWare Player but will apply your solution later on VmWare Workstation as well

Matt

[continuum]

please inspect a vmware.log file - it will give you the full path to the config.ini file.

In the config.ini hostwide memeory settings are stored - so it can be used to tweak memory handling.

So please attach the config.ini and a vmware.log to your next reply




_________________________

VMX-parameters- WS FAQ -[ MOAcd|http://sanbarrow.com/moa241.html] - VMDK-Handbook

[mattad]

So ok, the file contents of

C:\ProgramData\VMware\VMware Player\config.ini is:

installerDefaults.autoSoftwareUpdateEnabled = "no"

installerDefaults.componentDownloadEnabled = "yes"

installerDefaults.dataCollectionEnabled = "no"

That's all

Matt

[continuum]

then first of all configure memory.

menu > edit > preferences > memory

check the box "fit all ..."

also see http://sanbarrow.com/vmx/vmx-config-ini.html




_________________________

VMX-parameters- WS FAQ -[ MOAcd|http://sanbarrow.com/moa241.html] - VMDK-Handbook

[ksc]

It takes magic config options (welcome to the "unsupported" world) in the .vmx file. We don't expose a UI for these options.

Per-disk override:

scsi0:0.buffered = TRUE | FALSE (default FALSE), and the disk name is ideX:Y or scsiX:Y. If false, fall back to global options...

The global options are:

hard-disk.hostBuffer = "automatic" | "enabled" | "disabled" (default "automatic"). Automatic falls through to...

hard-disk.useUnbuffered = TRUE | FALSE (default TRUE on Windows, FALSE on Linux and Mac.)

The first option is newer; the second option is older and retained only as long as code stays clean.

We change defaults frequently, depending on known tuning properties / OS bugs and behaviors. Unless you have a specific reason to use otherwise, the defaults are almost always good enough. (But I gather you have a good reason to override the defaults).

When using buffered mode, the host OS decides when to write back. (We put it in the buffer cache, but don't explicitly flush).

[mattad]

>The global options are:

>hard-disk.hostBuffer = "automatic" | "enabled" | "disabled"  (default "automatic").  Automatic falls through to...

>hard-disk.useUnbuffered = TRUE | FALSE (default TRUE on Windows, FALSE on Linux and Mac.)

>The first option is newer; the second option is older and retained only as long as code stays clean.

Interesting, thank you.

I am intersted in global options.

To clarify:

- The default is hard-disk.hostBuffer=disabled

- If I switch to hard-disk.hostBuffer=enabled then I disable write through policy.

But when will the changes be flushed to real *.vmdk hard disc?

You write "the host OS decides when to write back"

Give me an idea when this is the case (for 32bit WinXP or 64bit Win7):

When CPU idle?

I expect at least when I do a shutdown of guestOS or hostOS.

Can I find out if there is any unflushed data?

A user option in menu "flush now" would be fine. Can you include such an option?

Thank you

Matt

[superciliousdud]

Hi,

Sorry to resurrect a long dead thread, but I have been using these options for ages, but recently tried to upgrade to Workstation 14.1.1, but I discovered that these options (and others I found) no longer work. All VMDK file I/O is unbuffered in 14.x all the known options in config.ini being used and therefore I/O is 1000x slower than under Workstation 12.5.x.

Is there an equivalent setting for the Workstation 14.x on a Windows 10 host?

Thanks

[superciliousdud]

Just in case anyone else is suffering this same issue, I have discovered an ugly, inelegant but working solution and I posted it in the other thread: Disk write cache broken in Workstation 14

[nivanov1]

---

Per-disk override:

scsi0:0.buffered = TRUE | FALSE (default FALSE), and the disk name is ideX:Y or scsiX:Y. If false, fall back to global options...

The global options are:

hard-disk.hostBuffer = "automatic" | "enabled" | "disabled" (default "automatic"). Automatic falls through to...

hard-disk.useUnbuffered = TRUE | FALSE (default TRUE on Windows, FALSE on Linux and Mac.)

---

I wonder if these parameters are still valid, particularly their default values, after the 10+ years? Also, is there a way to see the runtime values of these parameters after the VM starts?