Re: PostgreSQL advocacy

On 3/24/16, 3:09 PM, "Albe Laurenz" <laurenz(dot)albe(at)wien(dot)gv(dot)at> wrote:

>Jernigan, Kevin wrote:
>> Disk is only a single point of failure in RAC if you configure non-redundant storage.
>> In general, Oracle recommends triple mirroring to protect against disk failures,
>> as they have had many experiences over the years where customers with mirrored disks
>> would see consecutive disk failures within short periods of time.
>
>The single point of failure in Oracle RAC is the ASM file system.
>
>Yours,
>Laurenz Albe

Only if you misconfigure ASM for RAC: with RAC, an ASM instance will run on every RAC node, and if the ASM instance fails on any one node, the RAC instance on that node will go down, but the RAC instances on the other nodes will continue to run - so the database will remain accessible, though with fewer processors available.

If you configure ASM to implement at least dual mirroring for storage - and I’m pretty sure Oracle intentionally makes it hard to configure ASM without mirroring - then ASM will continue run through any single disk failure.

-KJ