SAP Mix

Ontape remote tape backup performance ...

Posted By: Rajasekaran, Rajesh
Date: Thursday, 30 January 2003, at 10:26 a.m.

Hi,

I would like to clarify a performance issue regarding the ontape remote
backups. We are running SAP R/3 in our site.We have two servers namely
DEV,SBX. The DEV box has got a DLT 7000 tape drive attached to it. DEV
system is configured to permit remote access to its tape drive for SBX to
perform its backups. I'm using "ontape" tool for Level 0/1 database backups
on these systems.

Till recently, we had both systems were on the same network (same
building). Though the tape drive is connected to DEV, our SBX level 1
backups completes inside 2.5 hrs. Now we moved our SBX system to a remote
site (different network,different office from DEV).

Since moving, i performed my first Level 1 backups. Its running almost for 2
days and still not completed. I could make out the Level 1 backups still
running and completed few dbspaces from the "onstat -g arc" command.

NOTE: Our Network infrastructure currently at remote site is not on par with
our main site and its way ahead in terms of speed,data transfer etc.

My point is
1) In an incremental backup(Level 1) on a not-so-heavily modified database
since last level-0 , database will spend more time on reading all the pages
for changes if any since last level 0. What are the chances of slow down on
reads of database pages so heavily in a remote site scenario ?

2) Most of the time,"onstat -u" reports "Y-AP--M" for the primary backup
thread. This means, it waits for some response from ontape to continue say
further scans on pages . Does ontape wait for any response from tape drive
? This could cause delay if has to come over the network quite frequently.

3) I know Network bottleneck cause some slow down in this case. Also, i
feel there could be a slow down within the box for a level 1 backups due to
some reasons.

Any comments/suggestions on other areas to monitor is greatly appreciated.

Thanks
Rajesh Rajasekaran
Informix Database Administrator
Forest Pharmaceuticals Inc.
314-493-7073 (Work)
314-662-6619 (Cell)
314-514-2457 (Home)

Messages In This Thread

• Ontape remote tape backup performance ...
  Rajasekaran, Rajesh -- Thursday, 30 January 2003, at 10:26 a.m.
  • FW: Ontape remote tape backup performance ...
    -- Tuesday, 4 February 2003, at 10:43 a.m.
  • RE: Ontape remote tape backup performance ...
    -- Tuesday, 4 February 2003, at 11:16 a.m.

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