ESXi 4.1 slow file transfer on HP DL380 G5

Solution 1:

It turns out that the Storage Adapter was exhibiting consistent write latency of 25 ms or more, even when the system was idle (no file transfers going on). This is a known issue with the HP Smart Array P400 when you do not have the BBWC (batery backedup write cache) module installed and write acceleration enabled.

Using the array configuration utility you can turn on write buffering, which did help some at the trade off of a slight risk of data loss. I have a 2 hr UPS in addition to a backup generator so I am not too worried about power loss.

Thanks for all your help

Solution 2:

HP has a new advisory related to this.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c01832427&jumpid=em_alerts_us-us_Jun11_xbu_all_all_1302806_87735_optionsandaccessoriesbladesystemproliantserverssoftware_critical_006_1

"HP recommends that customers purchase an optional Battery Backed Write Cache (BBWC) Module to achieve optimal disk subsystem performance on ProLiant G6 and G7-series servers running VMware ESXi 4.0 when the configuration includes the following Smart Array controllers:

Smart Array P410i Controllers Running VMware ESX 4.0
Smart Array P410 Controllers Running VMware ESX 4.0
Smart Array P411 Controllers Running VMware ESX 4.0
Smart Array P212 Controllers Running VMware ESX 4.0
Smart Array P712m Controllers Running VMware ESX 4.0
Note: This issue may affect other HP controllers not listed in this advisory that do not include Battery Backed Write Cache.

DETAILS Certain Virtual Machine (VM) operations such as cloning and powering on VMs may significantly impact disk subsystem performance on the VMs configured with the above mentioned Smart Array controllers that do not include Battery Backed Write Cache.

Note: When the Battery Backed Write Cache is not included in the configuration, even moderate disk I/O can negatively impact server performance."