RE: Slow AS400 performance

They are rechargeable.

But every rechargeable battery has a certain limit to its lifetime.

IBM plays it safe and requires them to be changed out every 1000 days.

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx 
> [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of 
> Peter.Colpaert@xxxxxxxxx
> Sent: Friday, April 21, 2006 2:03 AM
> To: Midrange Systems Technical Discussion
> Subject: RE: Slow AS400 performance
> 
> What I don't understand is why they don't use rechargeable batteries.
> 
> That way, when main power is on, the battery is always at 
> full charge, no 
> need to replace.
> 
> Or am I missing something?
> 
> Peter Colpaert
> Application Developer
> PLI - IT - Kontich, Belgium
> -----
> Yoda of Borg are we.  Futile is resistance, assimilated will you be.
> -----
> 
> 
> 
> "Christen, Duane J." <dchristen@xxxxxxxxxxxxx> 
> Sent by: midrange-l-bounces@xxxxxxxxxxxx
> 20/04/2006 22:55
> Please respond to
> Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
> 
> 
> To
> "'Midrange Systems Technical Discussion'" <midrange-l@xxxxxxxxxxxx>
> cc
> 
> Subject
> RE: Slow AS400 performance
> 
> 
> 
> 
> 
> 
> When data gets written to the cache it is considered "written 
> to disk" 
> even
> though it has not been written to disk yet. When main power 
> is lost the 
> data
> in the cache is protected by the battery for several days 
> (weeks?). When
> main power is restored the controller will write the data to 
> disk and you
> won't have lost a thing.
> If for some reason the data in the cache is lost you could 
> potentially 
> have
> to do a full restore on the system which for our main 
> production system
> could take 24-48 hours. (I don't know if RAID stripes are 
> stored in the
> cache before being written to disk, but that would make a 
> valid cache even
> more critical)
> 
> IBM has determined that at some point in the life of the 
> battery it will 
> not
> be able to protect the cache for the desired length of time 
> without main
> power, and warns you in plenty of time to replace it. If the 
> battery is 
> not
> replaced in time the cache is shut off and everything is 
> forced to disk 
> when
> it reaches the controller causing the performance degradation.
> 
> 
> Duane Christen
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