Rodrigo Barbosa wrote:
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On Fri, Jun 09, 2006 at 04:28:38PM -0500, Steve wrote:
Maybe you should take your time to read the manpage for "mt". Also, check the "blocksize" configuration for your tape drive.
I'm not talking about cpio -C or dump -b or tar -b. I'm talking about "mt setblk" and "blocksize" for stinit.
I'm quite familiar with mt's man page. I use 'setblk 0' for my clients' backups... but for compatibility reasons, not for performance ones. (Most OSes know about variable block size, BTW. Even SCO Open Server.) I see no reason to turn Bowie's simple question into a "this is really complicated" answer when it's not.
Yes, this IS a complicated question. Not because it is "technicaly complicatd" but because "many factors affect it".
If you use "setblk 0", you are using "Variable Blocksize". Which just makes it more complicated to calculate the throughput, since there is no way for you to know what block size will be under use in a given moment.
But I'll give you the benefit of the doubt. Since you say it is not a complicated issue, please give us the throughput he is getting for this DLT Unit.
Depends on the unit, of course. If the OS/Software is not delivering something reasonably close to that in the real world, then you have a problem. That's not complicated.
What Bowie asked was not what the rate was, but how he could measure what he is actually getting.
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.
-Steve