[Question]OnBar performance problem

[Yang, Heung-Soon]

I have question about OnBar performance.
One of my site uses OnBar with

Informix Product : Informix 7.23UC1
System : IBM SPNODE
OS : AIX 4.1.3
Backup Device : StorageTek TAPE Array
Storage Manager : SCH Storage Manager

The StorageTek TAPE Array can backup multiple host via network. And SCH
Storage Manager softwares are both installed on BACKUP SERVER and BACKUP

CLIENT machine. IDS 7.23UC1 is on BACKUP CLIENT machine.
The performance used to be 17 minutes for rootdbs. But now it takes
several hours to complete rootdbs backup without any change in
data/system!! Any other BACKUP CLIENT(including Informix on other
CLIENT)'s performance is not changing. Only this IDS on this IBM SPNODE
is problem.
And while onbar doing his job, I checked 'onstat -u'. The onbar
session's nread increases 16 per minutes.... On the other machine in
increases much faster.

So, we asked SCH Storage Manager engineer. He told us pump up the Read
Ahead parameters.(They are 50/30 now.) This would help ? Is there
anybody who has other ideas?

I attach onconfig/bar_action.log

Thanks in advance.

PS : Any other OLTP/DSS queries' performances are good just like before