Re: [Networker] Default for NSR_DEV_TAPE_FILE

Hi Peter.
Thanks to you for the reply.

My question was about parameter DEV_TAPE_FILE_SIZE, instead of 
about parameter DEV_BLOCK_SIZE. In any case I have found the answer.

I have defined the following environment variables in the
/etc/init.d/networker startup file:

NSR_DEV_BLOCK_SIZE_MSG=YES
NSR_DEV_TAPE_FILE_SIZE_MSG=YES
export NSR_DEV_BLOCK_SIZE_MSG NSR_DEV_TAPE_FILE_SIZE_MSG

In /nsr/logs/daemon.log file I found NSR default values for
DLT8000 drives:

   dlt8000 block size = 96 KB
   dlt8000 tape file size = 16384 blocks
   (about 1,5GB per tape file mark)

I tried to test tape writing speed with different value of BLOCK_SIZE
and different methods:
        Unix dd command (1GB file)
        Unix ufsdump command (/usr filesystem)
        Networker's generate_test_tape
        Networker's save command (satandalone local 1GB or 4GB file)
        Networker's savegrp with savesets on local host.

The listed above methods with the same BLOCK_SIZE gave out
different results.

I prefer "Networker's save" method for testing because I can see
how fast the NSR system writing tapes. 

The 4GB file has been created with:
    tar cf - /usr | dd of=./4Gtest bs=1k count=4000000

For each separate test I label tape with different block size.
Then I have mounted a tape in the tapedev (/dev/rmt/0cbn).
Then I have started the program (one or more times):
   /bin/time -p save -b 'TESTspool' ./4Gtest

(TAPE_FILE_SIZE - was not changed and defaults to 16384 blocks)

Results:
bs = 128k - speed 414,5 kb/s (8 tests)
bs = 160k - speed 439,1 kb/s (8 tests)
bs = 192k - speed 443,4 kb/s TAPE_FILE_SIZE = 8192 blocks (8 tests)
bs = 384k - speed 390,2 kb/s (3 tests)

Unfortunately I don't know how to improve backup performance :-(

Another question: what about NSR_DEVICE_BUFFER_SIZE parameter?
I have not found describtion of this parameter in Networker's
manuals (Legato and Sun EBS).


Server SunFire V210 (2CPU, 4GB RAM, 10000 rpm UltraSCSI disks)
HP ShureStore Tape Library with one QUANTUM DLT8000 drive
Interface UltraSCSI 160
Tapes DTL-IV (HP, Sony)
Tape drive and disks connected to same internal SCSI controller but
on different channels.
Solaris 10 sparc64 (with latest patches)
Networker 7.2.2 (Sun StorEdge EBS 7.2.build.422 with patch) 

> -----Original Message-----
> From: Legato NetWorker discussion 
> [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On Behalf Of Peter Viertel
> Sent: Saturday, June 17, 2006 4:35 AM
> To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
> Subject: Re: [Networker] Default for NSR_DEV_TAPE_FILE_SIZE parameter
> 
> In the 7.3 client and above, you will find 
> /usr/sbin/tape_perf_test which is a tool to systematically 
> try out different block sizes with different types of data..
> 
> It takes a long time to run , but on my sol10/ultra10 test 
> box it worked out that 384k was the best all round for 
> DLT8000... Roughly 11MB/sec, which shows just how old DLT8000 
> is getting...

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