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ESX 3i 3.5 performance issue

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  • ESX 3i 3.5 performance issue

    Hi all,

    Running into a performance problem on ESXi that I'm hoping someone else has seen before. Here's the background:

    ESX 3i 3.5.0 158375 running on Dell PowerVault NF500 (Same as PE 2950)

    2x Intel Xeon E5405 Quad Core 2.0 GHz
    18GB RAM
    Dell PERC 6i, host uses Megaraid SAS 1078 driver
    6x SATA 500GB drives configured as RAID 5 with dedicated hot spare.
    2x Broadcom 1Gbps integrated NIC, both connected @ 1000 Full

    Windows 2003 2x vCPU, 2GB RAM
    Windows 2003 2x vCPU, 1GB RAM
    Windows 2003 x64, 4x vCPU, 8GB RAM
    Windows 2000, 1x vCPU, 512MB RAM
    Windows 2000, 1x vCPU, 512MB RAM
    RHEL, 1x vCPU, 512MB RAM (VIMA)
    Windows 2003, 2x vCPU, 2GB RAM

    The problem is (mostly) with the x64 box. It runs Exchange 2007 as a multi-role server (Mailbox, Hub transport, Client access). It is one of 2 Exchange servers in the organization and hosts around 120 mailboxes.

    General performance of the server is ok. Client access seems fine. However, under load, it will simply freeze for a couple of seconds before resuming operation. This is accompanied by high ping times while the freeze is happening (ie, a continuous ping from another machine on the LAN or on the same host will show a jump from, say 0.25 ms to 3000 or more ms, and then resume normal operation). This freezing makes the VM infuriatingly difficult to manage from the console or from a TS session.

    Performance monitoring from VI client or from resxtop doesn't seem to show anything abnormal. General CPU usage of this machine during a busy workday is around 1000-1500 MHz, or 50-75% of a single core. The CPU utilization of the host as a whole is generally under 25% during the day. The disk utilization is also, in general, pretty low. I realize that the disk subsystem is not the fastest in the world, but it is, so far, OK for our purposes.

    Back history: This problem has cropped up in a previous incarnation of this server, again running ESXi. This time, the disk subsystem was a RAID 5 of 4x 500GB SATA drives and a RAID 1 of 2x 300GB 15k rpm SAS drives. The SAS drives were hosting a couple of Windows 2000 terminal servers that exhibited the same behavior under load-- this is why I think the problem is not the disk subsystem. But I welcome input.

    I have tried iterations of this server with 1, 2, and 4 vCPUs. All exhibit the same performance issues.

    I should note that the problem with this machine does not seem to carry over to the other machines... ie if I ping the x64 server and one of the other 2003 servers continuously from another machine the "pauses" or high pings don't seem to occur at the same time (or at all) on the other machine. However, as I said, I have seen the same problem with the previous Windows 2000 Terminal Servers on the same host, so I tend to think that it's not a problem with this specific VM.

    Hope this makes sense, let me know if anyone has any questions or things we can try. We are ready to invest in hardware to rectify this problem but are not sure where to invest... the general utilization of the host seems relatively low; if it is a disk problem the we could certainly look at some external storage but we don't want to simply throw money at the problem. We'd rather make an educated decision.

    Thanks for your help,

    Last edited by whosmatt; 9th September 2009, 08:10.

  • #2
    Re: ESX 3i 3.5 performance issue

    This sounds very similar top CPU contention problems on your ESX host.

    Look at this post of mine to start helping to troubleshoot the problem.
    Technodrone|@maishsk|Author of VMware vSphere Design
    VMware vExpert 2013-2010,VCAP5-DCA/DCD,VCP
    MSCA 2000/2003, MCSE 2000/2003
    A proud husband and father of 3 girls
    If you find the information useful please don't forget to give reputation points sigpic.

    Have a good one!!