Laptops + Virtual Servers

**Incognito** · 17 November 2010, 18:02

Originally posted by Spacecadet View Post

I might need to run a few development virtual servers on my laptop next year.

Before I look at possible upgrade options, does anyone have actual experience on the performance gains of quad core vs dual core?

Your disk will be your bottleneck before your processor.

**SupremeSpod** · 17 November 2010, 18:11

Originally posted by Incognito View Post

Your disk will be your bottleneck before your processor.

Yep. I would suggest getting a laptop with a couple of hard-disks and 'kin tonnes of RAM.

**Spacecadet** · 17 November 2010, 19:18

Originally posted by Incognito View Post

Your disk will be your bottleneck before your processor.

Fixable by using an SSD?
I really don't want a 17" laptop!

EDIT: I found a company that makes hard drive enclosures for the DVD drive bay
http://newmodeus.com

**Incognito** · 18 November 2010, 01:06

The problem you have (and it's the same with SSD) is contention. If your VM's are trying to read/write at the same time.

You can get away with it with a single drive, all I'm saying is that your disk performance will affect your laptop long before your compute performance.

http://www.codinghorror.com/blog/200...mance-tip.html

**yorkshireman** · 18 November 2010, 09:13

If they are just development servers, then is max. performance vital? I have a number of development (and production servers) running in the Amazon Cloud (which runs Xen for virtualisation) and they all use the "small" machine image because for most things "small" is good enough.

You may well find your existing laptop is sufficient for what you need. Have you test installed any VMs on it?

I always look at what Dell has on special offer at the time I am buying a new laptop - because sometimes these upgrades are virtually given away - particularly at their end of quarter/year. If you run a lot of simultaneous hosts then plenty of RAM would be my first priority.

Be careful if you use your laptop on battery much - then you need to consider whether the Quad core processor is going to reduce battery life.

Have you decided what host operating system you are going to run on the laptop yet?

**VectraMan** · 18 November 2010, 09:28

Originally posted by yorkshireman View Post

If they are just development servers, then is max. performance vital?

WHS. If the VMs are doing nothing 99% of the time, the only real impact they'll be having is the amount of RAM they'll use.

**doodab** · 18 November 2010, 10:36

If what you are doing is memory intensive then you'll need lots of memory, at least enough to support the host OS + whatever is allocated to the VMs without swapping.

Laptop disks are a bottleneck full stop, I've found that even using a separate external disk for the VMs. In my desktop I have 4 x 7.2k disks in a RAID array which improves things, however the best performance I have obtained is from the SSD in my laptop.

In fact when I got my first SSD I had it in an external enclosure (I bought it specifically to speed up an install of some commercial software on top of a windows + oracle DB VM that would run for 6-8 hours before failing) and apart from the install taking less than 20 minutes once I worked around all the foibles that caused it to fail I found that the windows running in the VM with the virtual disk located on the SSD was more responsive than the host OS installed on a 7.2k rpm laptop drive and I ended up using it for all sorts of everyday tasks.

For what I use it for (VMware workstation with linux or windows OS, oracle or SQL server databases, various J2EE app servers / web apps, often with another VM holding windows hosted dev tools, as well as a bit of faffing with computationally demanding stuff like FPGA synthesis in my spare time) I would certainly spend the money on an SSD over a quad-core processor, although of course having both wouldn't hurt.

**Sysman** · 18 November 2010, 13:01

Originally posted by SupremeSpod View Post

Yep. I would suggest getting a laptop with a couple of hard-disks and 'kin tonnes of RAM.

WHS. I've seen a dramatic difference from using 2 disks in my tower PC. When it was still a single disk system, doing anything hefty in the background would slow the installation of Windows into a VM to a snail's pace. Spreading the workload across 2 disks can make a huge difference.

A colleague recently got one of those combined SSD + hard disk jobbies for his MacBook Pro (a Seagate if I remember correctly). He fired up Word to demonstrate the difference, and I kid you not, it was there just as fast as other machines would bring an already launched app from the background. I gather that these combo disks are quite intelligent; they are using the SSD component as a cache for the hard disk component.

It wasn't outraegously expensive either.

**VectraMan** · 18 November 2010, 13:34

Originally posted by Sysman View Post

I gather that these combo disks are quite intelligent; they are using the SSD component as a cache for the hard disk component.

Do any VM hosts allow you to use RAM as a virtual disk? A lot of the time with VMs you want to use it, then revert back to the previous snapshop, and rather than writing to the VHD and then reverting it, it would make more sense to not write anything to disk and treat changes as temporary.

I have a build machine in a VM, and the total size of the checkout, temporary build files etc. is about 2.5GB. In theory if the host could emulate a hard disk in RAM, the whole thing could sit in RAM and be much faster, without the guest being any the wiser.

Laptops + Virtual Servers