Enable Write Disk Caching setting not saving

[Danny09]

Hi

I have recently built and configured a new server (HP DL360 G5 series), with two 70GB hard disks configured as the default Raid 1 in the hardware.

I have not promoted it to a domain controller and the only role set is that of a file server. One of the legacy applications that it is for requires 'Write Disk Caching' enabling.

So I go into the device manager disk properties and click on the policies tab to enable it. I get a message underneath the check box along the lines of:

"This device does not allow its write cache setting to be modified"

So, I check the box anyway and then when I go back in the setting hasn't saved at all. I have checked the following registry setting:

HKLM/System/CurrentControlSet/Enum/SCSI/VotreHardDisk/SerialNum/DeviceParameters/Disk/UserWriteCacheSetting which is set to a value of '1'.

I have checked the event log and got the following information:

Event Type: Warning
Event Source: Disk
Event Category: None
Event ID: 34
Date: 30/04/2007
Time: 09:18:19
User: N/A
Computer: xxxxxxxx
Description:
The driver disabled the write cache on device \Device\Harddisk0\DR0.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 0f 00 04 00 01 00 62 00 ......b.
0008: 00 00 00 00 22 00 04 80 ...."..
0010: 01 00 00 00 10 00 00 c0 .......À
0018: 00 00 00 00 00 00 00 00 ........
0020: 00 00 00 00 00 00 00 00 ........
0028: 00 00 00 00 ....

I have been into the BIOS and cannot see any settings related to DMA/Write caching etc. I have also tried the HP Array Configuration Utility which only has options for acceleration whch are on default settings. I'm really at a loss here, as far as I know these settings should be allowed.

I know that it is DEFINITELY not switched on though registry indicates differently because on the old NT4 server a file scan takes 25 seconds and on the new hardware it takes upwards of 5 minutes.

Can anyone please help me?

[Igor Karasik · Accepted solution]

Danny,
see my answer here:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1061968

"The Windows 2003 disk cache setting work only for direct connected disk drives (e.g. SCSI drives without RAID controller).
I think SmartArray doesn't allow Windows 2003 disk cache setting from windows,
you can set it only with ACU.
It's really two different things, shortly: logical disk doesn't support drive caching."

[Danny09]

Hi Igor, thanks for the suggestions.

I do not get the option to change the read/write settings in the ACU though. I will specify again that I have the disks set up as default hardware Raid 1; I have attached a screenshot of the ACU.

Thanks

[Igor Karasik]

>>I do not get the option to change the read/write settings in the ACU though

It is because P400i controller in default configuration doesn't have Battery-Backed Write Cache (BBWC). If you will add BBWC
you will have option to control Read/Write cache ration
(look for 512MB Battery-backed cache upgrade 405148-B21 )
BBWC will improve performance as well.

>>thanks for the suggestions.
Say thanks with HP points
http://forums1.itrc.hp.com/service/forums/helptips.do?#28

[Danny09]

Thanks Igor - really helpful.

Would I only require one of these cards or two? (i.e. one per disk or just a single?)

Thanks again!

[Igor Karasik]

>>Would I only require one of these cards or two? (i.e. one per disk or just a single?)


BBWC installed on SmartArray controller - one BBWC per one SmartArray and SmartArray P400i controller can support up to 18 SAS drives

Regards, Igor

[Danny09]

One last question Igor - I was asked if I only need the cache upgrade or the RAID controller. I specified just the cache upgrade as I assume the RAID controller is already in; allowing the RAID 1 setup in the first place?

Thanks

[Igor Karasik]

>>One last question Igor - I was asked if I >>only need the cache upgrade or the RAID >>controller. I specified just the cache >>upgrade as I assume the RAID controller is >>already in; allowing the RAID 1 setup in >>the first place?


You need to buy ONLY Battery-Backed Write Cache upgrade