[ale] writing to tape

[Geoffrey]

Scott Castaline wrote:
> On 02/02/2010 01:59 PM, Greg Freemyer wrote:
>> 2010/2/2 Björn Gustafsson<bg-ale at bjorng.net>:
>>> On Mon, Feb 1, 2010 at 10:31 AM, Geoffrey<lists at serioustechnology.com>  wrote:
>>>> Greg Freemyer wrote:
>>>>> What's your command line including pipes.
>>>> ssh servername "tar -cf - $BackupThis" | dd bs=10k of=/dev/nst0
>>> I don't know if it works with GNU tar, but you might want to try the
>>> -B switch and/or to set `-b 20' to explicitly match the dd blocksize.
>>> (20 should be the default though.)
>>>
>>> After quickly checking the GNU tar manpage, it seems to indicate that
>>> -B only works for reads, but it might be worth a try anyway.
>>>
>>> --
>>> Björn Gustafsson
>> tar is not the problem.  Its whatever the interconnect is between the machines.
>>
>> It is not keeping up with the tape drive so dd is stalling out on the
>> input from the comm channel and creating partial blocks on its output.
>>   dd is just not really a good tool for this use case.
>>
>> I've come across similar issues in the past.  My solution was to us
>> mbuffer as I said in a previous email.
>>
>> I think this is what I used<http://www.maier-komor.de/mbuffer.html>
>> but it was years ago.  Back then it was not really well supported and
>> I had to patch in some fixes..  To my surprise it is now in the
>> opensuse distro, so maybe others as well.
>>
>> Greg
> It's also available for Fedora:
> 
> [scott at ncc1701 ~]$ yum list mbuffer
> Loaded plugins: fastestmirror, presto, refresh-packagekit
> Available Packages
> mbuffer.x86_64              20091122-1.fc12                      updates

Not for RHEL though, not even epel. :(

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-- 
Until later, Geoffrey

"I predict future happiness for America if they can prevent
the government from wasting the labors of the people under
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