Re: hot backup archivelog the online-redo files and Oracle locks up

Comments below.
HJR "obakesan" <cjundieseastwd_at_powerup.com.au> wrote in message news:5Yw78.7175$T4.68682_at_nnrp.gol.com...
> HiYa
>
>
> assuming that my database is in archivelog mode (verifyable from
v$database),
> and that I have set the archiver process on by both the command alter
system
> archive log start followed up by log_archive_start=true entry in the
> init$ORACLE_SID.ora file
>
> I thought that this was all that was needed to get the database moving
along the
> right path for everything to operate well. The arhiver process then should
bump
> out stuff from the redo-logs (as they fill) into the archive
automatically.
>

You might want to look at log_archive_dest. There is a default destination to which archives will be sent if that's not set, from memory something like $ORACLE_HOME/dbs/logs (don't quote me on that), and Oracle may not always have permissions on that directory. Explicitly setting the parameter to somewhere it is definitely known it can archive is better.

> BTW when I do a ps -ef | grep $ORACLE_SID is one of these processes the
> archiver? hints on which one please??

Usually it has "arc0" in the name, in the same format as others you will see that have names like "dbw0", "pmon" and so on. It should be blindingly obvious.

>
> LOCKUPS
>
> One of the reasons why am I asking these things, is that today, when doing
a
> cold backup, the database hung on the shutdown immediate. This is strange,
and
> the only process open on it could have been either or a SQLPlus command
from my
> PC (Oracle is on a Linux machine) and perhaps a cron job that I run every
minute
> to insert 5 records into the database to have some sort of growth load on
the
> tables.
>

Not an uncommon problem, and probably totally unrelated to whether you are archiving or not. Lots of people have gotten into the habit of doing a shutdown abort, followed by a startup restrict, followed by a shutdown immediate.

> The process that ran the cold backup (shell script) hung on the
commandline, and
> so did other SQL plus prompts that I ran up (from an Xterm on the host)
rather
> strange.

Can't advise further without some more detail: like, what did your alert log say?

>
> I thought that perhaps the redo logs had filled (cant imagine why) and the
> server had come to a halt due to that. In desperation after some searches
on
> this topic, I ended killing all the processes that were that $ORACLE_SID
and
> that seemed to sort it out.
>
> I fired it up again from the commandline (sqlplus /nolog and connect / as
> sysdba) and it seems to be running fine now. I am running Oracle 8.1.6 on
> Miracle Linux 1.0 (yes, its Japanese and I'm not able to read an awful
lot)
>
>
> Back on the subject of the redo logs, these get moved to the archive area
by
> either the archiver proces when full, or when I issue an
> alter system switch logfile statement.
>
> My present understanding of these is that I need to keep all of these from
the
> time that the database is started in order to do recovery.
>

No. You only strictly need to keep archives from the time the last backup started (hot or cold, it makes no difference). But that rather assumes that you will always restore from the last backup. What happens if the last backup is damaged, is missing a file when it comes to be used, or is discovered itself to be corrupt? Then you would want to restore from a previous backup -but unless you've retained the archives since *that* backup, you won't be able to use it. Prudence suggests keeping several backups to hand, and all the archives needed to make sense of any of them.

> BUT IF I am doing a weekly shutdown, and full cold back up, it seems to me
that
> I only need to be strictly worried about the newly generated archive logs
from
> the point of startup again (assuming that after the weekly shutdown there
was no
> problem) At the weekend (sunday) shutdown, can I then flush the redo logs
to
> say off line storage and be able to start the week fresh?? Have I missed
> something here??
>

Well, moving the "unwanted" archives to offline storage sounds fine. Simply deleting them is a bit brave (ie, foolish), but since that's not what you are proposing, you should be fine.

Regards
HJR
> Finally, my filesystem, is raid 5 4 disks (striping and mirrored) so I
feel more
> comfortable that I wont loose just a disk, thus taking out my archive logs
or
> anything else (but will still copy them just in case.
>
> Ok ... this is getting long ... thanks for your time folks.
>
>
>
> See Ya
>
> --
> (when bandwidth gets better ;-)
>
> Chris Eastwood
> Photographer, Programmer, Motorcyclist and dingbat
>
> please remove u n d i e s for reply
Received on Mon Feb 04 2002 - 13:39:01 CST