Simon, did you ever have a situation where there was a partial write that
occurred and you recovered your db with the mirror copy?



> -----Original Message-----
> From: Simon Watson [SMTP:Simon.S.Watson AT SHELL.COM DOT BN]
> Sent: Thursday, April 22, 1999 9:32 PM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Re: DB mirroring vs. RAID
>
> We use ADSM Mirroring, and keep 3 copies!  We have both MirrorWrite
> (LOG & DB) parameters set to sequential.  Our DB is about 5 GB in size.
>  The cost of the disk required to do this pales in comparison to the
> business benefits of having a very robust configuration.
>
> Please be aware that Disk or Logical Volume mirroring will not provide
> the same level of protection for partial writes to the files, it will
> only protect from Hardware failures.  ADSM Mirroring will protect you
> from more types of failures & allow you more redundancy, ie more
> copies.  Remember ADSM provides these extra facilities because they add
> real value, over and above what the OS can provides.
>
> Of course you need to make sure the different Mirrors are on completely
> different hardware.  I suppose if you have buckets of money you could
> put the ADSM Mirrors on separate Hardware mirrored volumes or Raid
> Volumes, although this would impact performance.
>
> Regards,
> Simon