Hi,

WARNING: Enabling WC without BBU will cause data corruption when system is shutoff incorrectly.

I have found quite a few posting regarding performance issues with ESXi and LSI IR. Probably due to the write caching being disabled by default on these controllers.

You can change this with LSIUtil (http://www.lsi.com/DistributionSystem/AssetDocument/support/downloads/hbas/fibre_channel/hardware_drivers/LSIUtil%20Kit_1.60.zip), but by default this does not work on ESXi because it's slightly different:

/tmp # ./lsiutil

LSI Logic MPT Configuration Utility, Version 1.60, July 11, 2008

sh: /sbin/modprobe: not found

sh: /bin/mknod: not found

Couldn't open /dev/mptctl or /dev/mpt2ctl!

0 MPT Ports found

/tmp #

I made the following change to the source of LSIUtil and then it works on my ESXi 4.0:

--- lsiutil/mpt2sas_ctl.h       2008-04-17 20:30:40.000000000 +0200

+++ lsiutil.fix/mpt2sas_ctl.h   2009-07-05 22:58:58.000000000 +0200

@@ -56,8 +56,8 @@

/**

• HACK - changeme (MPT_MINOR = 220 )

  */

-#define MPT2SAS_MINOR          MPT_MINOR+1

-#define MPT2SAS_DEV_NAME       "mpt2ctl"

#define MPT2SAS_MINOR          MPT_MINOR2

+#define MPT2SAS_DEV_NAME       "mptctl_sas"

#define MPT2_MAGIC_NUMBER      'm'

#define MPT2_IOCTL_DEFAULT_TIMEOUT (10) /* in seconds */

-

/tmp # ./lsiutil.new

LSI Logic MPT Configuration Utility, Version 1.60, July 11, 2008

sh: /sbin/modprobe: not found

sh: /bin/mknod: not found

1 MPT Port found

     Port Name         Chip Vendor/Type/Rev    MPT Rev  Firmware Rev  IOC

1.  /proc/mpt/ioc0    LSI Logic SAS1068E B3     105      011c0200     0

Select a device:  LSI IR writecaching performance fix 1

1.  Identify firmware, BIOS, and/or FCode

2.  Download firmware (update the FLASH)

4.  Download/erase BIOS and/or FCode (update the FLASH)

8.  Scan for devices

10.  Change IOC settings (interrupt coalescing)

13.  Change SAS IO Unit settings

16.  Display attached devices

20.  Diagnostics

21.  RAID actions

22.  Reset bus

23.  Reset target

42.  Display operating system names for devices

45.  Concatenate SAS firmware and NVDATA files

59.  Dump PCI config space

60.  Show non-default settings

61.  Restore default settings

66.  Show SAS discovery errors

69.  Show board manufacturing information

97.  Reset SAS link, HARD RESET

98.  Reset SAS link

99.  Reset port

e   Enable expert mode in menus

p   Enable paged mode

w   Enable logging

Main menu, select an option:  LSI IR writecaching performance fix 21

1.  Show volumes

2.  Show physical disks

3.  Get volume state

4.  Wait for volume resync to complete

23.  Replace physical disk

26.  Disable drive firmware update mode

27.  Enable drive firmware update mode

30.  Create volume

31.  Delete volume

32.  Change volume settings

33.  Change volume name

50.  Create hot spare

51.  Delete hot spare

99.  Reset port

e   Enable expert mode in menus

p   Enable paged mode

w   Enable logging

RAID actions menu, select an option:  LSI IR writecaching performance fix 32

Volume 0 is Bus 0 Target 0, Type IM (Integrated Mirroring)

Volume 0 Settings:  write caching disabled, auto configure

Volume 0 draws from Hot Spare Pools:  0

Enable write caching:  LSI IR writecaching performance fix yes

Offline on SMART data:  LSI IR writecaching performance fix

Auto configuration:  LSI IR writecaching performance fix

Priority resync:  LSI IR writecaching performance fix

Hot Spare Pools (bitmask of pool numbers):  LSI IR writecaching performance fix

RAID ACTION returned IOCLogInfo = 00010005

RAID actions menu, select an option:  LSI IR writecaching performance fix 0

Main menu, select an option:  LSI IR writecaching performance fix 0

-

I was doing a slow SCP while enabling WC and you can see my improvement in the attached screenshot.

Let me know if it works for you.