Re: Storage Cache - WriteThrough or WriteBack

Hi!

I usually only tolerate write caching on storage subsystems when we are dealing with expensive boxes like EMCs Clariion or Symmetrix. I too have seen caches fail on entry level boxes like Sun A1000 etc...

Tanel.

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Thursday, August 14, 2003 8:39 AM

>
> I've begun a debate in my organisation about
> caches on storage systems.
> If an Oracle Database, including Redo Log files,
> is on RAID1 or RAID1+0 or RAID5 on the storage/SAN
> and the storage/SAN system provides a cache, should
> the cache be WriteThrough or WriteBack ?
>
> I prefer WriteThrough -- particularly when the
> Redo Log files are also on such external storage.
>
> The vendor talks of Mirrored-Caches and Battery-Backed Cache.
>
> In the past year, we've had one instance of the
> Cache itself failing and the Controller stopping all
> I/O to the storage and a couple of instances of
> Cache batteries being low/dead. {Should I/O be
> allowed to proceed if the Cache Batteries are dead
> or should the storage automatically switch to WriteThrough ?}
>
>
> Hemant K Chitale
> http://hkchital.tripod.com
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Hemant K Chitale
> INET: hkchital_at_singnet.com.sg
>
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-- 
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-- 
Author: Tanel Poder
  INET: tanel.poder.003_at_mail.ee

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