Clarification on ONBAR Backup performance issue..

Rajasekaran, Rajesh · Rajasekaran, Rajesh

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Hello all,

I would like to clarify regarding the performance degradation on our
backups.

Our weekly level0 backup normally completes in 10 hrs for 330gb database and
our daily incremental backup takes 1-1.5 hrs. We take the whole system
serial backup using ONBAR-VERITAS hook. Right now, we are not using parallel
backups for our environment. We have the Sun fire V880 with Solaris 9/ SAP
R3/IDS 7.31UD2XG. We noticed that for the past 2 level0, it has gone to 22
hrs and surprisingly our level 1 now takes 6 hrs for the past 2 days.

After some investigation, this is what i could make out. We have one dbspace
"psapbtab" with 153 GB with all 2 GB chunks. I agree the dbspace is deeper
in size,which will hamper the bkup performance etc. but until 2 weeks back i
got the whole psapbtab under 4.5 hrs. Level1 for this dbspace used to take
35m-1hr and now it takes 4-5 hrs. This means that the problem lies with this
dbspace only. I checked for the "old pages" bug running during the backup
and i couldnt find that "arc_very_old_pages()" with "onstat -g stk <tid> of
arcbackup1" at all. Nothing changed from the VERITAS side as well.

Also, we didnt re-start our systems for some time now. I see a total of 3
additional virtual portion shared memory segments on the "onstat -g seg" got
created. Here is our ONCONFIG onbar related parameters.

BAR_ACT_LOG /informix/PRD/bar_act.log
BAR_MAX_BACKUP 0
BAR_RETRY 1
#BAR_NB_XPORT_COUNT 10
BAR_NB_XPORT_COUNT 100
BAR_XFER_BUF_SIZE 31
Question

1) What could be the cause for the sudden performance degradation ?
2) Does the additional segments created in different physical location on
the shared memory cause the problem ? I am just wondering if this could be
the case, it might have degraded the whole database.

Please let me know if you need further inputs to pass on your
comments/suggestions.

Your suggestions are greatly appreciated.

Rajesh Rajasekaran
Informix Database Administrator
Forest Pharmaceuticals Inc.
(314) 493-7073
[email]rrajasekaran@forestpharm.com[/email]

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Hello all, 
    
   I would like to clarify regarding the =
performance degradation on our backups.
    
 Our weekly level0 backup normally completes in 10 =
hrs for 330gb database and our daily incremental backup takes 1-1.5 =
hrs. We take the whole system serial backup using ONBAR-VERITAS hook. =
Right now, we are not using parallel backups for our environment. We =
have the Sun fire V880 with Solaris 9/ SAP R3/IDS 7.31UD2XG. We noticed =
that for the past 2 level0, it has gone to 22 hrs and surprisingly our =
level 1 now takes 6 hrs for the past 2 days.

After some investigation, this is what i could make =
out. We have one dbspace "psapbtab" with 153 GB with all 2 GB =
chunks. I agree the dbspace is deeper in size,which will hamper the =
bkup performance etc. but until 2 weeks back i got the whole psapbtab =
under 4.5 hrs. Level1 for this dbspace used to take 35m-1hr and now it =
takes 4-5 hrs. This means that the problem lies with this dbspace =
only.  I checked for the "old pages" bug running during =
the backup and i couldnt find that "arc_very_old_pages()" =
with "onstat -g stk <tid> of arcbackup1" at all.  =
Nothing changed from the VERITAS side as well. 

Also, we didnt re-start our systems for some time =
now. I see a total of 3 additional virtual portion shared memory =
segments on the "onstat -g seg" got created.   Here =
is our ONCONFIG onbar related parameters.

BAR_ACT_LOG     =
/informix/PRD/bar_act.log
 BAR_MAX_BACKUP  0
 BAR_RETRY     &n bsp; =
1
 #BAR_NB_XPORT_COUNT 10
 BAR_NB_XPORT_COUNT 100
 BAR_XFER_BUF_SIZE 31
 Question


1) What could be the cause for the sudden performance =
degradation  ?
 2) Does the additional segments created in different =
physical location on the shared memory cause the problem ? I am just =
wondering if this could be the case, it might have degraded the whole =
database. 

 Please let me know if you need further inputs =
to pass on your comments/suggestions.


Your suggestions are greatly appreciated.


Rajesh Rajasekaran
 Informix Database Administrator
 Forest Pharmaceuticals Inc.
 (314) 493-7073
 rrajasekaran@forestpharm.com


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sending to informix-list

Fred Prose · Fred Prose

1. Is the backup done to a Veritas system that's on a different
(physical) server? If so, check the network. This is our situation
and over the years I've had the following network related problems:

a. The routes from server A to server B changed. Additional hops
translate to additional delays no matter how short their duration.

b. Has the device configuration for the network card changed? We've
had ours suddendly change from full to half duplex or 100 mbs to 10
mbs.

c. Remember, it's NEVER the network.

2. Does the veritas back up anything other than Informix through
Onbar? For example, standard UNIX files?

a. Are they taking longer also?
b. Could any other backups be running at the same time?

3. You say you haven't rebooted for a while. I think I'd schedule
this ASAP just to eliminate this as a possibility. My experience is
that many Informix problems (at least with AIX) disappear after a
reboot.

Clarification on ONBAR Backup performance issue..

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