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  • knowing just enough to be dangerous

    We are just a couple of guys with limited and hard won computer skills struggling to optimize the computers (no trained IT support at all). We know just enough to do what we are doing and not much more.

    Our business runs on 3 PC's running WinXP 64 as the host OS; each host can run up to 4 WinXP 32 Virtual Machines in VMware Workstation. We are in the process of converting the host OS to Ubuntu Linux v8.04. However it appears that 4 VM's are the practical limit we can run under either host OS configuration.

    The PC hardware of each host is as follows:
    Asus P5K motherboard
    Intel CPU (2.4 Gigabit Intel Core 2 Quad)
    8GB Ram
    3 SATA2 drives
    one Altheros L1 GB ethernet card 10/100/1000

    Questions
    1) We believe that part of the purpose of ESX server software is to run on multiple host machines in a network thus permitting the sharing of resources (CPU, RAM) between host machines. Is this correct?

    2) Can we run ESX server on this hardware? And if can, would the sharing of resources between machines result in improved performance and/or more machines being run on the same hardware?

    3) If the problem is hardware in the existing configuration, is there additional desktop hardware that could be added to the above machines to permit running a minimum cost ESX server network (hardware RAID, additional ethernet card, other?)?

    4) If desktop hardware is insufficient, what hardware would be recommended to run a minimum cost ESX server? Running 24/7 is not mission critical and we are relatively unconcerned about hardware reliability as our business will not collapse if we suffer some downtime. Expandability of the system would however be a concern. While there is no top-end to the number of Virtual Machine we might need to run ~20 appears at this time to be a reasonable target.

  • #2
    Re: knowing just enough to be dangerous

    Originally posted by kriemer View Post
    We are just a couple of guys with limited and hard won computer skills struggling to optimize the computers (no trained IT support at all). We know just enough to do what we are doing and not much more.

    Our business runs on 3 PC's running WinXP 64 as the host OS; each host can run up to 4 WinXP 32 Virtual Machines in VMware Workstation. We are in the process of converting the host OS to Ubuntu Linux v8.04. However it appears that 4 VM's are the practical limit we can run under either host OS configuration.

    The PC hardware of each host is as follows:
    Asus P5K motherboard
    Intel CPU (2.4 Gigabit Intel Core 2 Quad)
    8GB Ram
    3 SATA2 drives
    one Altheros L1 GB ethernet card 10/100/1000

    Questions
    1) We believe that part of the purpose of ESX server software is to run on multiple host machines in a network thus permitting the sharing of resources (CPU, RAM) between host machines. Is this correct?
    There are several advantages to ESX in conjunction with Virtual Infrastructure (ESX + VirtualCenter), particularly when you add shared storage into the mix whether that's SAN, iSCSI, or NFS. Going down the road of ESX and shared storage costs thousands of dollars for a bare minimum setup and can get pricey very quick but ESX is the cadillac of virtualization. Be sure you fully understand what your specific business needs are before you are convinced by someone to spend your money on ESX. It may not be the right virtualization solution for you.

    Originally posted by kriemer View Post
    2) Can we run ESX server on this hardware? And if can, would the sharing of resources between machines result in improved performance and/or more machines being run on the same hardware?
    Is it supported by VMware? No.

    Will it run on your hardware - very slim chance. The big question marks are the SATA controller and the network card. ESX requires strict following of the HCL (hardware compatibility list). You can purchase servers off ebay for is little as a few hundred dollars that will run ESX if you want to get started with a minimal setup.

    Originally posted by kriemer View Post
    3) If the problem is hardware in the existing configuration, is there additional desktop hardware that could be added to the above machines to permit running a minimum cost ESX server network (hardware RAID, additional ethernet card, other?)?
    In the land of ESX, one needs to get out of the mindset of running on desktop class hardware. ESX is an enterprise class solution geared for redundancy, scalability, and high availability, among other things. Desktop hardware gets you none of that and really has no business running ESX other than for a proof of concept or testing.

    Originally posted by kriemer View Post
    4) If desktop hardware is insufficient, what hardware would be recommended to run a minimum cost ESX server? Running 24/7 is not mission critical and we are relatively unconcerned about hardware reliability as our business will not collapse if we suffer some downtime. Expandability of the system would however be a concern. While there is no top-end to the number of Virtual Machine we might need to run ~20 appears at this time to be a reasonable target.
    As I said previously, there is a ton of hardware on ebay that will run ESX for a few hundred bucks. I work strictly with Compaq/HP equipment so I can only talk about those particular models. Inexpensive models that have worked well for me in the past in my home lab are as follows:

    Compaq Proliant DL380, DL380G2, DL380G3, etc. Dual processor servers that will support a maximum of 2GB of RAM in the first generation models, and higher amounts of RAM plus Intel hyperthreading in the newer models (G3 and above).

    Compaq Proliant 6400R. This is a 4 way PIII box that you'll find with processors ranging in speed up to 550MHz. Maximum of 4GB of RAM. I ran older versions of GSX and ESX on two of these servers for 3+ years and they were great. After a while they just got too slow for my patience.

    Compaq Proliant DL580. This is the new version of the 6400. It has P3 900'ishMHz processors.

    Compaq DL760. The first generation of this box is a PIII 8 way box which will take I believe 16GB of RAM. I sold my 8 way for $300-$400 last year. This box is a beast and will run a lot of VMs. Newer generations of this server are more expensive and will obviously be faster with P4 processors.

    HP Proliant DL580G2. These are what I have racked currently in my basement. Quad P4 2.5GHz processors with 12GB RAM each. You can pick these up with 2-4GB RAM for well under a thousand dollars. I know a guy who has a whole warehouse of these things that have come off lease. It's where I bought mine last year. He's real good to deal with.

    Based on "rule of thumb" virtual machines, assume
    -You can run 4 VMs per processor core (ie. a 4 way box can run 16 VMs)
    -In your ESX host, have 4 GB RAM per processor core (ie in a 4 way box, you should have 16GB of RAM in your ESX host)
    -Minimum of 4 disk spindles to hold your VMs. The more spindles, the better. This is where affordable iSCSI really adds value. If you can add several SATA drives to that whitebox you have, it may make a good iSCSI target. rPath Openfiler Linux makes a great iSCSI/NFS server and the software is free. I've been using it with much success for well over a year.

    Based on the number of potential VMs you want to run (20), I'd go for the DL580G2s. Minimum of 2 so you've got some hardware redundancy or at least spare parts if your main server gives up the ghost. I know you said you can suffer a little down time but if you drop 10-20 servers and it takes you a few days to get them back, I think you'll be hurting a lot more than you realize. This is where hardware redundancy adds tremendous value to your solution whether you cluster 2 or more servers together, or simply keep one in the closet as a hot standby or for spare parts.

    Other considerations you need to think about are upgrading the RAID array controllers in your ESX servers for maximum disk I/O performance. Once you start to run multiple VMs, you'll begin to see contention for disk especially with a smaller number of disk spindles. Disk throughput starts to become important.

    You'll need VMware ESX compatible network cards. I have dealer online where I purchase Broadcom GB NICs for $9.95 a piece. The chipsets on these NICs are on the ESX HCL and work wonderfully so I bought them in bulk.

    I hope that helps.

    Jas
    Last edited by jasonboche; 6th June 2008, 03:36.
    VCDX3 #34, VCDX4, VCDX5, VCAP4-DCA #14, VCAP4-DCD #35, VCAP5-DCD, VCPx4, vEXPERTx4, MCSEx3, MCSAx2, MCP, CCAx2, A+
    boche.net - VMware Virtualization Evangelist
    My advice has no warranties. Follow at your own risk.

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