Vista Tutorial - slow performance on VM

My VMs have slowed to a crawl. I'm running Virtual Server 2005R2 on a
W2K3 box with 16GB RAM quad cpu. Host server seems to be ok on RAM and
CPU utilization, so does the VM but I can't pinpoint why all the sudden
the VMs are running slow. Any suggestions? Thanks.

--

I/O throughput? If your disk subsystem gets bogged down, everything will
slow to a crawl.

Another possibility is memory fragmentation. If the host box has been up for
a long time, it might have fragmented memory, especially if this is a 32-bit
2k3 box.

--
Charlie.
http://msmvps.com/blogs/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel

"Geb" <geb@_nospam.com> wrote in message
news:%23OlMCzJBJHA.2476@xxxxxx

Charlie Russel - MVP wrote:
I just rebooted, a little improvement but still slow. I turned on
performance monitor and the ave.disk queue lenght is always at 100.
Does this indicate a problem?

--

Sure sounds like it to me. What's your I/O subsystem look like on that box?
What's your disk fragmentation look like? Are you running a nice, wide,
array on high performance SAS disks? or a 3 disk RAID5 on SATA?

--
Charlie.
http://msmvps.com/blogs/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel

"Geb" <geb@_nospam.com> wrote in message
news:ejXHkWXBJHA.2060@xxxxxx

Charlie Russel - MVP wrote:

The ave disk queue length seems to be not pegging at 100 at the moment.
It's going up and down wildly depending on what's going on the VMs.

Fragmentation Info:

Volume (C
Volume size = 466 GB
Cluster size = 4KB
Used Space = 180 GB
Free Space = 286 GB
Percent free sp = 61 %
Volume fragmentation
Total fragmentation = 3%
File framentation = 7%
Free space fragmentation = %
File Fragmentation
Total files = 24,807
Ave file size = 8 MB
Total fragmented files = 229
Total excess fragmenents = 4,462
Ave fragements per file = 1.17
Pagefile fragmentation
Page file size = 2.00 GB
Total fragements = 1
Folder fragmentation
Total folders = 2,666
Fragmented folders = 3
Excess folder fragements = 11
Master File Table (MFT) fragmentation
Total MFT size = 27 MB
MFT record count = 27,658
Percent MFT in use = 98
Total MFT fragements = 2


I have 2 HP 500GB SATA non-hot plug 7,200 RPM 1" hard drives (mirrored)
on a LSI Adapter, SAS 3000 series.


Hope that gives you a clearer picture.



--

Yup, gives me a good picture.

You're I/O bound. SATA drives are simply getting more than they can handle.
Honestly, Virtualization is a great thing, but it _seriously_ stresses the
I/O subsystem. Then you've put all your stuff on the system drive, creating
additional load. And finally, to compound the problem, you've got 4k
clusters - I like something more on the order of 16k clusters or even larger
on VHD storage.

If you're going to use SATA drives, you've be FAR better off having more,
but smaller drives, configured in an array. I don't know what your physical
server looks like, but if you can put in an array of 6 or 8 smaller SATA (or
better yet, SAS) drives, you'll change the picture completely. To give you
an idea, here's how my main Hyper-V server is configured. (It's an HP
ML-350G5 with dual 5130 CPUs and a SmartArray P400 controller, plus an
additioanl Adaptec SAS controller.)

2 - 36 GB SAS drives - RAID-1 - C: drive, system
2 - 320 GB SATA drives - RAID-0 - D: drive - temporary, disposable storage.
ISOs, etc.
8 - 72 GB, 2.5", 15k SAS drives - RAID-5 - E: drive - my VHDs reside here.

Even that isn't perfect - I'd do better with RAID-10 for the VHD drive, but
it would mean swapping out the 72GB drives for 144's and the budget won't
handle that right now.

--
Charlie.
http://msmvps.com/blogs/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel

"Geb" <geb@_nospam.com> wrote in message
news:e1XnPNtBJHA.4172@xxxxxx

Charlie Russel - MVP wrote:

Thanks for the info. I usually get DL380s which have better disk I/O
but I had to resort to using a DL145 for the virtual server.

Btw, how is easy/hard is it to move a VM to another physical hardware,
would it be just moving a few files (vhd, etc)?

Thanks.



--

Yup, I've got a DL-380 here - with 8x SAS drives on that one too, but only
10k. I/O is good on it, though, you're right. A far better choice than
the 145 with only a pair of SATA drives.)

Moving a VM to new hardware is fairly simple. If you're running Hyper-V, you
should export the VM and then move the files, and import on the target end.
If Virtual Server, you just move the files, and recreate the VM, pointing to
the VHDs. In both cases, you're likely to have to recreate the networking to
match. (That first boot of the VM can be a bit slow if you don't match it up
exactly.)

Another alternative, and one I really like, is using SCVMM to manage VM
locations. It does a really good job of moving VMs and managing which ones
are where. You'll need the (soon to be released) 2008 version to handle
Hyper-V. The 2007 version only does VS.

--
Charlie.
http://msmvps.com/blogs/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel

"Geb" <geb@_nospam.com> wrote in message
news:e$WZJtGCJHA.1224@xxxxxx