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ML370 G6 w/ P410i Write Cache Questions....

garr79
Occasional Visitor

ML370 G6 w/ P410i Write Cache Questions....

Hello,

 

I have an ML370 G6 w/ P410i wi/ 256Mb cache.  When looking at the hpacucli output for the controller, it shows
(25% Read / 75% write) for the Accelerater Ratio.  It also shows "Drive Write Cache: Disabled". 

 

Does this mean that since the Write Cache is disabled, the controller is basically using 100% of the 256Mb of cache for "Reads"?

 

Thanks

1 REPLY

Re: ML370 G6 w/ P410i Write Cache Questions....

Drive Write Cache is a cache present on the physical hard drive and does similar function as the array accelerator. It offloads read/write commands from the controller and leaves the controller free for further I/O operations.

 

 

In the scenario presented by you, this feature of hard drive is reported as disabled.  Please note that this feature is disabled by default on all HP hard drives. The reason is that if there is a power interruption or if a hot-plug drive were to be removed,(rare scenarios), then the write operations stored on the cache of the physical hard drive is lost and results in data loss.

 

In the stated scenario, there is data protection through the array accelerator and that 25% is allocated for read operations and 75% for write operations of the 256 MB and not as suspected by you.

 

Hope the above is able to shed some light on the stated situation.

 

Regards,

 

Vijayasarathy

I work for HP
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