W dniu 22.10.2021 o 12:35, David Crayford pisze:
On 22/10/2021 5:59 pm, Radoslaw Skorupka wrote:
W dniu 22.10.2021 o 03:12, David Crayford pisze:
On 21/10/2021 7:31 am, Bill Johnson wrote:
I do almost everything important via app with a mainframe on the
back end. Banking, health records, retail shopping, insurance
claims, investing. And with very high confidence the transactions
are secure, fast, & always available. Not sure how more modern the
mainframe could be actually.
Bill J
I would suggest that almost all of those companies (banks, retail,
insurance etc) that run mainframes run a significant portion of
their IT systems on distributed systems. I recently met a software
architect from a bank who told me that the explosion of internet
banking app usage has pushed up the TCO of their mainframe to
unacceptable levels. 70% of those transactions were reads (folks
checking their bank balances on their phones). Their solution was
use Apache Kafka to replicate the data to Apache Cassandra and only
hit the mainframe for writes.
BTDT, but not on Kafka. Indeed, the "cache system" ran up to 40%
transaction.
Sounds good? Imagine: 40% less workload...
NO
There are light and heavy CICS transactions and cached ones were light.
Proof: some day the cache stopped working due to system failure.
During rush hours.
Observations from mainframe side: number of transactions per second
blew up. Average response time ...decreased a little bit.
I was really happy reporting it to management.
The link I provided was Australia's largest (and a world top 20) bank
with millions of transactions a day. They're not stupid, production
technology choices are critical which is probably why IBM have spent
$$ making sure Kafka runs ok on z/OS.
Caching isn't a new idea. It's a common CICS design pattern using TS
so you don't have to make an expensive call to DB2 or IMS. The
customer solution is not call the mainframe for read transactions.
It's not uncommon, it starting to become pervasive. Writes are a
different matter.
The link I did not provide was a bank with hundreds of millions
transactions a day.
And I didn't say caching is stupid or "they" are stupid.
I just told a story. Real story. And paid attention to misleading
indicator.
--
Radoslaw Skorupka
Lodz, Poland
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