Running multiple virtual machines from a single SSD?

[blizeH]

Hi all,

Just a very quick question - I run a lot of VMs on my desktop PC (5 VMs, with 3 hard drives)

Unfortunately I cannot add more because my computer is a Dell and I'm already having to use a screw for where a fan (or something) goes to hold a hard drive in position, so I have a choice to make...

Should I ditch one of my hard drives for a much smaller SSD, and would I notice a big performance increase if (for example) I ran 4 VMs from that single SSD, and one on my storage hard drive? (freeing up the drive with the Windows install on in the process)

Thanks

[majortom1981]

  On 23/09/2011 at 13:51, blizeH said:

Hi all,

Just a very quick question - I run a lot of VMs on my desktop PC (5 VMs, with 3 hard drives)

Unfortunately I cannot add more because my computer is a Dell and I'm already having to use a screw for where a fan (or something) goes to hold a hard drive in position, so I have a choice to make...

Should I ditch one of my hard drives for a much smaller SSD, and would I notice a big performance increase if (for example) I ran 4 VMs from that single SSD, and one on my storage hard drive? (freeing up the drive with the Windows install on in the process)

Thanks

You would need a lot of space and a lot of money for that. SSD drives are still expensive verses space you get.

[blizeH]

  On 23/09/2011 at 13:54, majortom1981 said:

You would need a lot of space and a lot of money for that. SSD drives are still expensive verses space you get.

Thanks, but each VM requires maybe 15GB (at most) of space to run an old Windows XP install, so an 80GB drive could be perfect for it

[majortom1981]

What are the vm's running?

[blizeH]

Just various web servers for me to test on, to be honest the actual CPU usage on them is very small that it seems okay on my i7, just the hard drive(s) crunch like crazy at times, especially when booting them up

[cybertimber2008]

  On 23/09/2011 at 13:51, blizeH said:

Should I ditch one of my hard drives for a much smaller SSD, and would I notice a big performance increase if (for example) I ran 4 VMs from that single SSD, and one on my storage hard drive? (freeing up the drive with the Windows install on in the process)

You likely have a lot of contention if you have multiple VMs running from a single hard drive (or even two). A SSD will definitley help you relieve some of that, and at the least, as you said, free up your Windows drive.

You will notice a performace increase. Will it be big? Depends. But you will see one.

Make sure though if you plan to run from a SSD, that you reconfigure your VM manager to see the drive as SSD and apply TRIM, etc. I know VirtualBox added support. Otherwise you'll wear out your drive prematurely, but it would take awhile.

[blizeH]

Ah you're a star, thank you - lots of things to consider then.

I've actually moved one of the VMs off the drive with the Windows install and have seen a big performance increase already... I'm thinking to run a hard drive check every so often, and if there are any problems (that can't be fixed) quickly switch out that drive for an SSD one maybe, but at the moment it could be wasteful when I'm not sure just how much of a performance boost I'll see?

Thanks again

[neoraptor]

IMHO You are going to trash the ssd quickly. VMs do lots of reads/writes.

If choose to do so, insure you have disabled last access time for files and directories, turned off swap and any logging you can and put as much as possible ram so more disc content is buffered (there was some hidden option to set how much ram is used for buffering in XP).

Also set your vm disk sizes to a fixed value so they don't shrink/expand and disable defragmentation (and indexing) from both host and guest.

[blizeH]

Ah nice one, thank you - some great advice... should I do that stuff even before making the switch to SSD? Would it help with my current setup?

Ideally I'd just have 5 hard drives (or 6, one for each VM, and an SSD for my main drive!) but that isn't possible unfortunately, unless I get a whole new PC ;_;

[remixedcat]

are you running vmware vsphere? that is a bare metal hypervisor that runs the VMs with no underlying operating system needed.

This is an ideal solution. Most people in the hosting industry use this. You start from there and work your way up to a nice vmware datacenter setup

http://www.vmware.com/products/vsphere/overview.html

http://www.vmware.com/products/datacenter-virtualization/

[garethevans1986]

Why not buy a cheap server from ebay?

£100 will get you something decent to run VMWare on.

GE