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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.os.vms
Subject: Re: RX2800 sporadic disk I/O slowdowns
Date: Sun, 20 Oct 2024 21:17:27 -0000 (UTC)
Organization: A noiseless patient Spider
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On Sun, 20 Oct 2024 08:42:37 -0500, Craig A. Berry wrote:

> On 10/19/24 10:51 PM, Lawrence D'Oliveiro wrote:
>>
>> On Sat, 19 Oct 2024 21:52:16 -0400, Arne Vajhøj wrote:
>> 
>>> The context is one where data loss is not acceptable.
>> 
>> Data loss is unavoidable. If the power goes out, all computations in
>> progress get lost. There’s no way around that.
> 
> Yes, there is.  It's called battery-backed cache on a RAID controller,
> and when the power goes out, any writes in progress still get written
> because the battery supplies power to the cache.

Unless the battery fails. Then you discover that your disk controller was 
lying to you about saving the data you thought it was saving.