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Conference ssdevo::hsj40_product

Title:HSJ30/40 Product Conference
Moderator:SSDEVO::EDMONDS
Created:Tue Jul 13 1993
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1264
Total number of notes:4958

1230.0. "hsj42 with all ac power loss plan" by TPOMC2::FREDTSENG () Thu Apr 10 1997 07:40

    Hi ;
    
    Could someone told me the formal procedure when the hsj40 or hsz40...
    products with ac power loss,what should we do to save the write cache
    data? because the power maybe need 4 hours or more to 1 day for recover
    the power system. we know the battery will discharge very quickly with
    cache module load. I had tried to remove one pair battery from one of
    the hsj42 controller to keep battery good, but this method will cause
    the other(with battery) controller with inconsistence cache data. And
    some data maybe lost I guess!
    
    If ac power lost we keep the symptom. The controller of hsj42 may
    discharge all the battery power. Then the system can't startup if 
    cache_policy=a till the battery charge go from bad to good. And the 
    same time ? what's situation of the disk data , save or not ?
    
    Need some "Top guy" help !!
    
    Regards.
    
    Fred .
T.RTitleUserPersonal
Name		DateLines
1230.1TINCUP::RIDGEI don't know where I'm at, but I'm nearly there!Thu Apr 10 1997 19:2619
The design requirements/goal was that the battery be able to maintain 
memory for a minimum of 100 hours.   That is a very conservative number 
and there is evidence that it would be maintained 2x or more of that 
figure  with 2 fully charged batteries.   

If the power off condition exceeds that amount of time, then its likely that
the customer has more pressing problems at that point than the loss of
data in cache......like his/her home refrigerator at home has defrosted AND
the significant other is calling!!

You are correct, with cache_policy=A, at startup time, you will not be able
to bring a raidset up until good battery status is attained.  


There is consistency information in written in cache to ensure that what 
is in cache is still good data so that when things are operational, that 
the data will be appropriately delivered to the media and be accurate.

They are trying to protect the data!
1230.2battery can't work for 100 hours discharge really.TPOVC::FREDTSENGSat Apr 12 1997 04:0515
    Soory for later feedback!
    
    The situation for 100 hours could be accepted. But we happen to have 5
    hsj42 (10 *hsj40) controller lost power suddently for 2 hours.Then ups
    charge for 1 hours , lost power again for 3 hours. But when power back,
    only one hsj40 battery charge good in 15 minutes.The other all display
    with batterly low. then waiting 12 hours later, some of the controller 
    becomes bad battery. The battery rev is "B01", some batteries without
    rev labels though they are new. Could this be battery production
    problem? I had thease events for 3 times. For such situations, what
    action should we done ?
    
    Thanks,
    
    Fred.