RE: Where do I learn about SAN backup?

AFAIK, the Flash Copy is only possible with a SAN. On the iSeries the 'cheap' SANs are the V7000 and the V9000. I'm not sure if the V7000 is totally out of the picture yet or not.

There are more expensive SANs than the V9000 available... They have some more features.


Paul E Musselman
PaulMmn@xxxxxxxxxxxxx

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Joe Pluta
Sent: Wednesday, August 30, 2017 3:15 PM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: Where do I learn about SAN backup?


Thanks everyone for your input.

I've been chasing this down on my own after all your comments and I've
come to some initial conclusions that I'll be bringing back to the business.

It looks like there are some very powerful possibilities here, and given
the integration of FlashCopy to BRMS it makes it almost a no-brainer,
except maybe for the learning curve.  The biggest question I have is
whether all of this magic is:

A) Only possible with a SAN
B) Possible with non-SAN but much easier with SAN
C) Little or no difference between SAN and non-SAN

We're talking low double-digits TB here, and a whole lot of that is IFS
documents, so I'm just trying to get my arms around the overall
cost/benefit arguments of a SAN.

Thanks again, everyone!



On 8/24/2017 7:59 PM, PaulMmn wrote:

And I disagree with one of Steve's statements.  See below (I've
rearranged some of Steve's comments).
--Paul E Musselman

The physical amount of disk space on the SAN used by BACKUP, is
directly related to the amount of data blocks which changed on
PRODUCTION after the flash copy started.  No data is copied between
partitions.

    I disagree.

(...)

There are several possible events:

(...)

The data is duplicated in blocks, not bytes.  The SAN has a bit table
with one bit for every block of data in the LPAR.  So if you're
planning to change 10 bytes in a data block, the entire block is
copied to the Backup LPAR.  Then your 10 bytes is updated.  If the
same data space in the Production LPAR has already been updated, there
is already a copy of that data in the Backup LPAR; it is only copied
once.


--Paul E Musselman