[CentOS] Tape drive throughput

[Steve]

Rodrigo Barbosa wrote:

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>On Fri, Jun 09, 2006 at 05:38:30PM -0500, Steve wrote:
>  
>
>>>>But I would be *very* interested to know how you could calculate the 
>>>>total throughput of a random drive if you *did* know the fixed block size.
>>>>        
>>>>
>>>Knowing the blocksize used, I would just tell him to use "mt setblk"
>>>to the same block size, then use "dump" to dump a random ammount
>>>of that to the tape. Dump will provide you with the throughtput rate
>>>you want.
>>>
>>>If you don't know the blocksize, or if you are using variable (0),
>>>you really can't measure it outside the specific application you 
>>>are using to write the data to the tape.
>>>
>>>      
>>>
>>Seems like it would be easier to just run it through something like 
>>buffer, mbuffer, or dbuffer and have one of those report the value 
>>second by second, in kilobytes per second.
>>    
>>
>
>Should work too, but is it possible to do with the application he is
>using ?
>
>Actually, what IS the application he is using ?
>
>  
>
Good question.

Let's assume that he is using "BackMeUpNow Proprietary Editition(tm)" 
newly ported from Win32 and running under Winelib. 

Another strategy, then, might be to do something like:

# Clear the cache
dd if=/dev/hda of=/dev/null bs=1M count=2048

# Run the backup utility
./BackMeUpNowProForLinux


And then monitor it with:

vmstat 60

What gets written to tape has to be read from disk first, right?

-Steve