Re: Real application clustering in postgres.

On 3/6/20 8:55 AM, Laurenz Albe wrote:
> On Fri, 2020-03-06 at 03:25 -0600, Ron wrote:
>>> RAC is not really a high availability solution: because of the shared
>>> storage, it has a sibgle point of failure.
>> This is utter nonsense.  Dual redundant storage controllers
>> connected to disks in RAID-10 configurations have been around for at
>> least 25 years.
>>
>> Oracle got it's clustering technology from DEC, and I know
>> that works.  Cluster members, storage controllers and disks have all
>> gone down, while the database and application keep on humming along.
> I am not saying that it is buggy, it is limited by design.
>
> If you have mirrored disks, and you write junk (e.g, because of
> a flaw in a fibre channel cable, something I have witnessed),
> then you have two perfectly fine copies of the junk.

Why do you have just one FC path?

> I am not saying the (physical) disk is the single point of failure, the
> (logical) file system is (Oracle calls it ASM / tablespace, but it is
> still a file system).

Why isn't the filesystem (or RDBMS) throwing checksum errors?  This was 
standard stuff in legacy Enterprise RDBMSs 20 years ago.

-- 
Angular momentum makes the world go 'round.