Re: Mean Time Between Failure for the IBM AS400

On Thu, 17 Jan 2002, John Ross wrote:

> We have an IBM AS400 - 730 and 720. Luckily for us, our 2 systems have had
> 0 down time in many years.

This is probably not true.  Do you ever install PTFs or upgrades?  How
about backing up your system?  You do have down time.  You may not have
any failures per se but you do have down time.

It seems to me that compared to other stable systems (i.e. non-Microsoft)
OS/400 has more downtime due to backup/IPL.  That is probably due to the
database backup (which isn't necessary on my other systems since they
don't run the DB).  But OS/400 requires the system to be in a restricted
state throughout the backup process.  This can require a lot of downtime
every night.

Can anyone comment on:

1.  How to minimize downtime due to backup.  For example, how to get a
good "snapshot" of the data while minimizing the time spent in a
restricted state.

2.  How downtime due to system maintainance (daily backup, PTFs,
upgrades, etc.) compares between OS/400 and other stable OSes (like
Solaris, OS/390, other unix).  Does anyone run DBs on something besides
iSeries and can comment on their backup process?

Surely someone like the New York Stock Exchange has a lot of data to
backup every day and also can't allow their machine to be restricted for
very long.  How do they do it?

James Rich
james@eaerich.com