How to verifiy Backup Throughput speeds

[comtec17]

Hello,
Using NetWorker 7.1 on HP-UX 11.0, LTO Gen2 tape. I am very new to NetWorker and was wondering how can I tell how fast my backups are being written to tape? I run the test backup from command line. Is there a log file that will give me this info?

Thanks in advance.

 

[605]

look at /nsr/logs/daemon.log or /nsr/logs/messages.

 

[Martin999]

Further to this, once the speed has been deduced you need to ensure you are running at a optimum speed. LTO2 drives should be able to write someware around 30MB/sec - so if your only getting 10MB/sec (sustained) then something is up.

For a given amount of tape there will always by the same amount of data stored, therefore if you feed the data out to the tapes to slowly (eg. bottlenect someware on system) the drives have to keep stopping, rewinding a bit then starting off again, known as 'showshining' it wears drives out quicker.

On the other extream, if you try and feed to much data, savesets end up being queued and your backup takes longer.

It is a balance between server parallelism and no of target sessions on drives.

Server parallelism - no of savegroups being streamed out, default is four. Target sessions is the no of sessions Networker should send to the drive, so a Parallism of 4 and target sessions set to 2 would mean that 2 drives would be required, or if one drive was available only, it would take approx twice as long to run the backup as if two drives were available. Setting the target sessions to 4 would allow all the streams to be written at once, therefore making more efficient use of the drive. Unfortunately, this is trial and error.

Martin

 

[605]

A good tool to achieve max performance is the "bigasm" test.
Please read any "Performance Tuning Guide" for details, for example from tis URL:

http://web1.legato.com/infodev/publications/NetWorker/perftun/7.0/perftune_7.0.pdf

 

[fazil1]

Hello,
I belive Nwadmin is still viable option on Unix, check monitor tab and look at the speed at which the drives are being writen too , it it apppears slower then increase your paralism, device sessions and stream more cleints\saveset at once to increase the backup performance.
bombay4U@hotmail.com

 

[Martin999]

Indeed, nwadmin and nsrshow are valid tools, and these show the point in time spped of data to tape. However, need to be aware that depending on what is being backed up depends on the speed which is why it's better to take an average - less you want to sit there watching a backup for n hours ...

 

[Martin999]

... sorry brain fade, meant nsrwatch ...