Re: PowerHA and Journaling

Hello,

It is generally advised to use journaling in the total scope of High
Availability... depending on your RTO,RPO
(for complex data base and for IFS when IFS files are part of business
transaction...)

but I am not aware of any mandatory use of journaling with PowerHA.

As you mention, PowerHA operates at the ASP/disk level (page written
permanently to disk are mirrored to another system ) Journaling operates
at the object level.

I have a customer using powerHA to replicate an IASP with a data base and
IFS storage and does not use any journaling function on these objects.

Paul




From: Aaron Bartell <aaronbartell@xxxxxxxxx>
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Date: 09/03/2016 16:06
Subject: PowerHA and Journaling
Sent by: "MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx>



I am working through an IFS issue and just learned that the mmap(n1) API
doesn't work correctly when the IFS *DIR is journaled. Ouch for any
replication vendors that use IFS journaling for businesses that use the
IFS
for more than file storage (i.e. open source development).

My understanding is that PowerHA operates at a lower level than journaling
to accomplish replication but I am having trouble finding that fact in
documentation(n2) because it seems iCluster *does* rely on journaling, so
there's still a lot of journaling talk in the PowerHA docs.

n1 - http://bit.ly/v71-mmap
n2 - http://bit.ly/sg247994

The question: Does PowerHA require journals?

Aaron Bartell
litmis.com - Services for open source on IBM i