HP Smart Array P212 configuration questions

[cookieme]

I'm setting up an ML110 G6 with a Smart Array P212/256MB (with battery) controller for my lab. I have 2 x Seagate Constellation ES 500 GB SAS drives (ST3500414SS) connected to the controller in RAID1. The server is connected to an APC UPS.

I will run ESXi 4.1 from a USB key and use the local datastore for multiple VMs such as AD, DNS, DHCP, Zimbra email server, Windows 7 desktops, vCenter etc.

I would like some help with the configuration of these controller settings:

- Stripe size

- Array Accelerator (Cache) Ratio

- Transformation Priority

- Rebuild Priority

- Surface Scan Delay

- Enable write cache when battery/capacitor not present or not completely charged

- Physical drive write cache state

Thanks

[DSTAVERT]

I don't know that you would gain anything by making changes. Defaults usually work for most situations. Test various settings if you want to see the effects of a change.

[AndreTheGiant]

If you have the battery (as written) enable the cache.

And maybe consider to balance the read/write cache (but this depends of the type of your workloads).

Andre

[DSTAVERT]

I hadn't noticed that write caching wasn"t enabled. That should be enabled if the battery is installed. If I remember it won"t enable until the battery is charged.

[cookieme]

Andrew M wrote:

If you have the battery (as written) enable the cache.

And maybe consider to balance the read/write cache (but this depends of the type of your workloads).

Andre

Yep I have the battery and it is fully charged. The Array Accelerator option is enabled, but there are two other cache options:

- Enable write cache when battery/capacitor not present or not completely charged

- Physical drive write cache state

Should I enable these two options also?

Regarding the read/write cache setting are you suggesting that I change the setting Array Accelerator (Cache) Ratio to 50/50?

Thanks

[DSTAVERT]

Do not enable this.

- Enable write cache when battery/capacitor not present or not completely charged

Do enable this

 Physical drive write cache state

The default read write should be fine the way it is. Write caching is usually the most critical for virtual performance and you don't have a lot of cache.

[cookieme]

David Stavert wrote:

Do not enable this.

- Enable write cache when battery/capacitor not present or not completely charged

Do enable this

 Physical drive write cache state

The default read write should be fine the way it is. Write caching is usually the most critical for virtual performance and you don't have a lot of cache.

Ok I'll make those changes. I'm not entirely sure how the "Physical drive write cache" differs from the "Accelerator Cache".

Can you please explain the difference.

[DSTAVERT]

Don't enable either one of them.

Just leave the settings as they are. No changes.

I misread Physical Drive write caching. Physical Drive caching is using the small cache on the directly physical drive. In the case of a power failure anything in the controller cache would be saved and written to the disks when power was restored. Anything on the disk cache would be lost and there is a potential for data corruption.

[cookieme]

Ok, I'll leave everything default. Thanks DSTAVERT!

Btw I have tried to award you the "correct answer", but nothing happens when I click the button. Is there something wrong with the board?

[DSTAVERT]

There are issues left over from the recent forum update. Points is one of them. I wouldn't worry about it. Just mark it answered if that is possible.

[cookieme]

Done. Thanks again.

[DSTAVERT]

Very welcome.