johnpet
1 Copper

2850: does embedded perc have battery backed write cache?

in the 2850 (and 2800) does the embedded perc controller have bbwc?
if so how much?
if the controller fails is the battery backed info (the raid config info) on a daughter board that can be removed so the raid config info is saved before the motherboard is replaced?
 
on the add-in perc4/dc 1-internal 1-external (i think), which i'm sure has bbwc, is there a daughterboard that can be removed if the controller fails?
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3 Replies
JA96621
1 Nickel

Re: 2850: does embedded perc have battery backed write cache?

"Optional single channel ROMB with battery backed 256MB of cache for internal drives"
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JA96621
1 Nickel

Re: 2850: does embedded perc have battery backed write cache?

Sorry, only put in a response to he Subject line last time and not the whole message.

Configuration is saved with the controller and also stored on the drives themselves.

No daughterboard on this system.

You might be thinking of the backplane.

It doesn't store configuration.

You replace the MB and then get the configuration that is stored on the drives.

This is the same whether onboard or a controller card.

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B_Segurson
2 Iron

Re: 2850: does embedded perc have battery backed write cache?

The battery backed cache retains data through power glitches and outages of limited duration.
 
The original question was if the cache memory remains valid after a controller failure while replacing the motherboard.    There is no way that memory contents' validity can be guaranteed while replacing components.   The battery backed cache is a DIMM plug in module with battery onboard.  As with any card or DIMM it is possible to inadvertently short out pins when removing and reinserting the DIMM.  Therefore there is absolutely no guarantee of data validity through component replacement operations.  
 
Battery backed cache is an operational feature, for times when the system is functional and no component replacement is in progress.   As mentioned it preserves unwrittern data through power failures.
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