Re: big, fast, etc, was is Vax addressing sane today

John Levine <johnl@taugh.com> writes:

It appears that Michael S  <already5chosen@yahoo.com> said:

There's also a rule of thumb about databases that says one system of
performance 100 is much better than 100 systems of performance 1
because those 100 systems will spend all their time contending for
database locks.

>
How many transactions per minute does world's biggest company need at
peak hours?

>
Ten years ago Visa could process 56,000 messages/second. It must be a
lot more now. I think a transaction is two or four messages depending
on the transaction type.
>

Is not this number small relatively to capabilities of
even 15 y.o. dual-Xeon server with few dozens of spinning rust disks?

>
Uh, no, it is not.

The way I would design this for a machine with that little IOPS is as
an in-memory database, with transactions written to a log on RAID-1
(on two or three of the HDDs), and a snapshot of the in-memory
database written to disk repeatedly, with copy-on-write to get a
consistent snapshot.  The 8 cores of a 2009-vintage the dual-Xeon
machine should be easily capable of doing it, but the question is if
the machine has enough RAM for the database.  Our dual-Xeon system
from IIRC 2007 has 24GB of RAM, not sure how big it could be
configured; OTOH, we have a single-Xeon system from 2009 or so with
32GB of RAM (and there were bigger Xeons in the market at the time).

- anton
--
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>