2011-04-04

VMWare Server : IOWait Performance Tuning

• 因為經常遇到 IOWait 的問題，所以找一下別人是怎麼解決的。
• <參考> ​Gutsy and Vmware-Server – you’re in for some pain
• 首先修改 /etc/vmware/config

  --- /etc/vmware/config.bak	2011-04-04 22:21:13.000000000 +0800
  +++ /etc/vmware/config	2011-04-06 10:20:42.000000000 +0800
  @@ -22,4 +22,7 @@
   product.name = "VMware Server"
   # Beginning of the block added by the VMware VIX software
   vix.libdir = "/usr/lib/vmware-vix/lib"
  +# 11-04-04: Enhance performance - by Jazz
  +prefvmx.useRecommendedLockedMemSize = "TRUE"
  +prefvmx.minVmMemPct = "100"
   # End of the block added by the VMware VIX software
  

• 其次修改經常發生 IOWait 的虛擬機器 vmx 設定檔

  Trac_Pool.vmx

  @@ -49 +49 @@
   debugStub.linuxOffsets = "0x0,0xffffffff,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0"
   
   extendedConfigFile = "Trac_Pool.vmxf"
  +
  +sched.mem.pshare.enable = "FALSE"
  +mainMem.useNamedFile = "FALSE"
  +MemTrimRate = "0"
  +MemAllowAutoScaleDown = "FALSE"

• 另外，不確定是否因為我用單檔 VMDK 所以造成記憶體的 filesytem cache 太高，所以定期用 crontab 清掉一些 cache

  0 * * * * /usr/sbin/ntpdate-debian > /dev/null 2>&1
  0 * * * * echo 1 > /proc/sys/vm/drop_caches
  5 * * * * echo 3 > /proc/sys/vm/drop_caches
  

• 還可以用 vmware-vdiskmanager 進行虛擬硬碟的檢查跟重組、縮小 - <參考> ​How To Shrink VMware Virtual Disk Files (.vmdk)

  # 對 myDisk.vmdk 進行重組(defragment)
  vmware-vdiskmanager -d myDisk.vmdk
  # 把 myDisk.vmdk 釋出沒有用到的空白空間（shrink）
  vmware-vdiskmanager -k myDisk.vmdk
  # 把 sourceDisk.vmdk 拷貝成 type 為 0 (single growable virtual disk) 的 destinationDisk.vmdk
  vmware-vdiskmanager -r sourceDisk.vmdk -t 0 destinationDisk.vmdk
  # 把 myDisk.vmdk 容量擴大到 36GB
  vmware-vdiskmanager -x 36GB myDisk.vmdk