RE: Slow AS400 performance

["Lapeyre, Francis" <FLAPEYRE@xxxxxxxx>]

Because, when the mains power is cut off and the battery is dead, the cache
would be lost, resulting in corruption. So if the battery is dead, the disk
controller plays it safe and does not use a cache. You can't predict power
failures.


Francis 



-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Colin Williams
Sent: Thursday, April 20, 2006 3:25 PM
To: Midrange Systems Technical Discussion
Subject: Re: Slow AS400 performance

I have no idea about the design of these controllers,

but presumably if they are there as battery backup in the event of a power
failure, to ensure that all writes go to disk,

why do they affect performance if they die whilst mains power is available?
Why cant these controllers just use mains power whilst its available?