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Re: Unix + SSA disk

From: Nebojsa Petrovic <nebacar_at_eunet.yu>
Date: Wed, 4 Nov 1998 07:53:37 +0100
Message-ID: <71p4r9$7vk$1@SOLAIR2.EUnet.yu>

George Dau wrote in message <363f7072.75846431_at_isappp>...
>"Nebojsa Petrovic" <nebacar_at_eunet.yu> wrote:
>
>]This question is not exactly for Oracle DBA but maybe someone can help me.
>]
>]We have IBM R6000 model F40 and Unix (in one box with own power supply and
>]UPS) with SSA disk (in another box with own power supply with common or
>]other UPS)
>]
>]F40 and UPS communication with serial connection. If power failure is
occur
>]UPS shutdown the F40, but SSA disk stil work over until UPS have energy,
>]and then stop (on the same way as power failure occur without UPS). If
power
>]failure occur relativly offten and long time UPS maybe crash.
>]
>]Is there anyway to resolve problem with SSA disk and UPS.
>]
>
>I think that you don't have a problem. The SSA's I have worked with have
>internal (lithium) batteries to backup their cache, and would have flushed
that
>to disk within minutes of the F40 being shutdown by the UPS.
>
>Since the F40 is down, and the cache in the SSA has been flushed, the power
can
>cycle to the disks without affecting the data. It may cause physical
problems
>though if it keeps happening of a period of time.
>

Hi George,
I think that we misunderstand.
Well, not problem with cache and data in SSA system . Problem is actually what will hapen with UPS if power failure occur relativly offten and long time. In UPS, battery hold the regular voltage (220 or 100V) while the protected system (e.g. computer) not shutdown. After that computer not consumption of power (or very small) and this situation can stay for long time.

When connect SSA on UPS and when power failure occur SSA disk flushed cache and data will be save, but what will be happen with UPS; SSA will continue work (disk plate rotate...) and consumption power from UPS (SSA disks can't "shutdown"). After some period battery will leak!!!. How can I prevent this situation Received on Wed Nov 04 1998 - 00:53:37 CST

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