Re: Miserable Disks

this is from memory because I'm not a SAN admin anymore, but the first 4 drives of enclosure 0 grab space for the OS (CX600 - Win NT, CX700 - Win 2000 or XP ) for each SP and space to destage memory if there's a hardware (i.e. bad disk) or power failure. It works. Our ups failed twice and it destaged the memory and powered down just fine.

steve

On Jun 4, 2006, at 12:17 AM, Henry Poras wrote:

> I asked our SA about this and he said that the write cache is non
> volatile as long as it is enabled and the backup battery system has
> power. This means that the write cache should be small enough to
> allow it to flush its contents before the battery depowers, but
> given this, there is nothing to worry about.
>
> As I am still learning EMC stuff, is this true? Are there other
> things that can go wrong with write cache?
>
> Thanks.
>
> Henry
>
>
>
> Jared Still wrote:
>
>> Comments inline.
>>
>> On 5/25/06, *Mark Brinsmead* <pythianbrinsmead_at_gmail.com
>> <mailto:pythianbrinsmead_at_gmail.com>> wrote:
>>
>> (*) Get the biggest cache you can afford. (Make sure it's
>> *really* non-volatile. Wolfgang
>> never mentioned what happens to your database when you lose the
>> contents of the write
>> cache, but *I* got a taste! And it wasn't pleasant!)
>>
>>
>> Yes, I had experience with that 2 weeks ago on a CX700.
>> Definitely unpleasant.
>>
>> EMC claimed that we should have disable the write cache
>> prior to powering down the SAN.
>>
>> I have since learned that the support tech in question was blowing
>> smoke.
>>
>>
>> --
>> Jared Still
>> Certifiable Oracle DBA and Part Time Perl Evangelist
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>

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