[gentoo-user] Best file system type for running vmware images?

[gentoo-user] Best file system type for running vmware images?

[Mark Knecht]

Hi,
   I'm wondering if anyone has opinions (on this list? Right...) as to
the best file system type for running vmware images of Windows XP. As
best I can tell an 8GB C: drive shows up as 4x 2GB files and 1.5GB
DRAM is modeled in a file of its own:

firefly Mark-XP1 # ls -la
total 9291380
drwxr-xr-x 5 mark users       4096 Mar  8 06:05 .
drwxr-xr-t 4 mark users       4096 Mar  7 15:53 ..
-rw------- 1 mark mark  1593835520 Mar  8 09:41
564daa93-5e87-f134-7796-e68c82de64ee.vmem
drwxrwxrwx 2 mark mark        4096 Mar  8 06:05
564daa93-5e87-f134-7796-e68c82de64ee.vmem.lck
-rw------- 1 mark users 2147221504 Mar  8 09:41 Mark-XP1-f001.vmdk
-rw------- 1 mark users 2147221504 Mar  8 09:41 Mark-XP1-f002.vmdk
-rw------- 1 mark users 2147221504 Mar  8 09:26 Mark-XP1-f003.vmdk
-rw------- 1 mark users 2147221504 Mar  8 09:41 Mark-XP1-f004.vmdk
-rw------- 1 mark users    1048576 Feb  5 09:30 Mark-XP1-f005.vmdk
-rw------- 1 mark users        526 Mar  8 06:06 Mark-XP1.vmdk
drwxrwxrwx 2 mark mark        4096 Mar  8 06:05 Mark-XP1.vmdk.lck
-rw------- 1 mark users          0 Feb  5 09:28 Mark-XP1.vmsd
-rwxr-xr-x 1 mark users       1398 Mar  8 06:05 Mark-XP1.vmx
drwxrwxrwx 2 mark mark        4096 Mar  8 06:04 Mark-XP1.vmx.lck
-rw------- 1 mark users        263 Feb  5 09:27 Mark-XP1.vmxf
-rw------- 1 mark users       8684 Mar  8 06:05 nvram
-rw-r--r-- 1 mark mark      105208 Mar  8 05:38 vmware-0.log
-rw-r--r-- 1 mark mark      106644 Mar  7 16:26 vmware-1.log
-rw-r--r-- 1 mark mark      105163 Mar  7 13:55 vmware-2.log
-rw-r--r-- 1 mark mark      103535 Mar  8 08:40 vmware.log
firefly Mark-XP1 #

   I suppose that as Windows is operating within this image Windows
thinks it is reading or writing to what it considers a file but vmware
gets in the middle to somehow map where a small file is within this
larger 2GB entity.

   My usage model is heavily read dominated. I write stock data into a
file once and then read it hundreds of times to do work. I'm
investigating RAID striping to increase read speed but no matter what
the files appear to always be 2GB so I suspect XFS, Reiser or
something other than ext3 that I'm currently using would possibly make
a difference?

   But would it be a big difference? How would I test it? I.e. - not
that XFS is or isn't a good file system but that it actually helps
with vmware operation?

   My current system is AMD64, 4GB DRAM, i5 Core which is 4 processor
threads. Target machine is AMD64, i7 Core or possibly dual XEON, 16GB,
4-6 monitors and multiple 1TB+ drives in some sort of RAID mainly for
speed, and then additionally an external RAID for backup.

   Any ideas warmly appreciated.

Thanks,
Mark

Re: [gentoo-user] Best file system type for running vmware images?

[Roberto Waltman]

Mark Knecht wrote:
> Hi,
>    I'm wondering if anyone has opinions (on this list? Right...) as to
> the best file system type for running vmware images of Windows XP. As
> best I can tell an 8GB C: drive shows up as 4x 2GB files and 1.5GB
> DRAM is modeled in a file of its own:
>
>...
>
>    I suppose that as Windows is operating within this image Windows
> thinks it is reading or writing to what it considers a file but vmware
> gets in the middle to somehow map where a small file is within this
> larger 2GB entity.

Correct.

>    My usage model is heavily read dominated. I write stock data into a
> file once and then read it hundreds of times to do work. I'm
> investigating RAID striping to increase read speed but no matter what
> the files appear to always be 2GB so I suspect XFS, Reiser or
> something other than ext3 that I'm currently using would possibly make
> a difference?

The 2GB limit can be set at virtual disk creation time. Older versions
of NTFS can not deal with bigger files, so VMWare gives you the option
of splitting a larger disk image into 2GB segments. As far as I know, you
can not change this after a virtual disk is created.

>    But would it be a big difference? How would I test it?

Run iozone  ( http://www.iozone.org/ )

>    Any ideas warmly appreciated.
> Mark

You can create a new virtual disk as a single segment and copy your data
into it. The disk read/write performance may not change much...

You can also give the virtual machine direct access to a partition or
physical disk, bypassing the host file system. Again, this may or not be
better (speedwise)


Roberto Waltman

Re: [gentoo-user] Best file system type for running vmware images?

[Florian Philipp]

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Mark Knecht schrieb:
> Hi,
>    I'm wondering if anyone has opinions (on this list? Right...) as to
> the best file system type for running vmware images of Windows XP. As
> best I can tell an 8GB C: drive shows up as 4x 2GB files and 1.5GB
> DRAM is modeled in a file of its own:
> 
[...]I suspect XFS, Reiser or
> something other than ext3 that I'm currently using would possibly make
> a difference?
> 
>    But would it be a big difference? How would I test it? I.e. - not
> that XFS is or isn't a good file system but that it actually helps
> with vmware operation?
> 
>    My current system is AMD64, 4GB DRAM, i5 Core which is 4 processor
> threads. Target machine is AMD64, i7 Core or possibly dual XEON, 16GB,
> 4-6 monitors and multiple 1TB+ drives in some sort of RAID mainly for
> speed, and then additionally an external RAID for backup.
> 

As an educated guess, I would say that ext4's usage of extents should
improve the performance on large files by a measurable margin.

As one of the last filesystem drivers which still use the Big Kernel
Lock, I would also guess that Reiserfs might not scale well to heavily
multithreaded usage or multicore CPUs. However, I cannot say if this has
any kind of noticable effect on 4-8 core machines.

As Roberto Waltman already suggested, benchmarking is the way to go.


By the way, as you mention RAID. Note that on pure read operations, a
RAID1 can be as good or even better than a RAID0 because read operations
can be distributed freely among the disks since all of them contain all
data.

Hope this helps
Florian Philipp


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