DL385 P400 Array wite cache enable issue

[JohnASC]

Hi All

I have just installed the BBWC 512 kit onto my P400 array controller in an effort to enable write caching on the disk (server 2003 SP2). The reason for this was to prevent the disk latency errors I recieved for this server from my MOM interface (and event viewer). The problem is that even after installing the BBWC I still cant enable write caching either via the windows interface or the ACU CLI. Is there something I am missing or is there a limitation to the P400 that I dont know about or have not been able to find

[Patrick Terlisten]

Hello John,

is the battery of the BBWC module fully loaded? At which do you try to enable write caching? At the logical drive or the underlaying physical disk?

Best regards,
Patrick

[JohnASC]

The BBWC has been installed for a couple of weeks now so I can only assume that the battery is fully loaded.

I have tried to enable it at the Logical side (using the policies settings in the properties of the logical drive in Device Manager) and I have also tried the ACU CLI as I assumed it made changes to the physical side of it. Will I need to bounce the server to get into the ORCA to make some changes there?

[Patrick Terlisten]

Hello,

there is no need, and AFAIK no way, to enable write cache in the ORCA. Just run ACU and set the policy.

Did you get any error message while enabling write cache??

Best regards,
Patrick

[JohnASC]

in the ACU CLI I type in the "controller slot=1 modify drivewritecache=enable"

I come up with the warning regarding data loss and I say "yes" to continue

It then produces an error saying this operation is not supported with the current configuration. Use the "show" command on the devices to show additio0nal details about the configuration.

controller slot=1 show

Smart Array P400 in Slot 1
Bus Interface: PCI
Slot: 1
Serial Number: PA2240J9SU8BK0
Cache Serial Number: PA2270H9SUP0T1
RAID 6 (ADG) Status: Enabled
RAID 6 (ADG) Enabler Status: Enabled
Controller Status: OK
Chassis Slot:
Hardware Revision: Rev B
Firmware Version: 1.18
Rebuild Priority: Low
Expand Priority: Low
Surface Scan Delay: 15 sec
Cache Board Present: True
Cache Status: OK
Accelerator Ratio: 50% Read / 50% Write
Total Cache Size: 512 MB
Battery Pack Count: 1
Battery Status: OK
Array: A
Interface Type: SAS
Unused Space: 0 MB
Status: OK

Logical Drive: 1
Size: 273.4 GB
Fault Tolerance: RAID 5
Heads: 255
Sectors Per Track: 32
Cylinders: 65535
Stripe Size: 64 KB
Status: OK
Array Accelerator: Enabled
Unique Identifier: 600508B100104A39535538424B300004
Disk Name: \\.\PhysicalDrive0
Mount Points: C:\ 273.4 GB

physicaldrive 1:1
Port: 2I
Box: 1
Bay: 1
Status: OK
Drive Type: Data Drive
Interface Type: SAS
Size: 146 GB
Rotational Speed: 10000
Firmware Revision: HPD5
Serial Number: 3NM0V23C00009730UVSV
Model: HP DG146ABAB4
physicaldrive 1:2
Port: 2I
Box: 1
Bay: 2
Status: OK
Drive Type: Data Drive
Interface Type: SAS
Size: 146 GB
Rotational Speed: 10000
Firmware Revision: HPD5
Serial Number: 3NM0N3EJ00009730X292
Model: HP DG146ABAB4
physicaldrive 1:3
Port: 2I
Box: 1
Bay: 3
Status: OK
Drive Type: Data Drive
Interface Type: SAS
Size: 146 GB
Rotational Speed: 10000
Firmware Revision: HPD5
Serial Number: 3NM0SATX00009730SJ8C
Model: HP DG146ABAB4

I cant see anything wrong with this configuration. Maybe you can.

[Patrick Terlisten]

No, anything is allright.

**Accelerator Ratio: 50% Read / 50% Write**

50% of the installed cache is used as write-cache, 50% as read-cache

**Array Accelerator: Enabled**

Write-Cache is enabled for logical drive 1.

Best regards,
Patrick

[JohnASC]

Then why does it generate the error when I try and enable it via the ACU CLI?

And why does it say, when I try and enable it via device manager -> Logical Volumn Properties -> policies. it says this device doen not allow its write cache settings to be modified?

I just want to stop these disk Latency erros I am getting for this server in my MOM console

[Patrick Terlisten]

Hello,

you can't enable the write cache for a physical drive. Some time ago here was a thread with the same "problem".

The device manager message is false report: The disk you see, is a "virtual" disk, presented by the Smart Array. Windows can't message this type of disks.

Best regards,
Patrick

[JohnASC]

Ok then

Thanks for your time and effort. Much appreciated

[JohnASC]

once again thanks