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From: Werner Griessl <croot@btp1da.phy.uni-bayreuth.de>
Message-Id: <199612090824.JAA27943@btp1da.phy.uni-bayreuth.de>
Subject: Re: rdump slow
In-Reply-To: <199612072019.VAA22287@uriah.heep.sax.de> from J Wunsch at "Dec 7, 96 09:19:54 pm"
To: joerg_wunsch@uriah.heep.sax.de
Date: Mon, 9 Dec 1996 09:24:18 +0100 (CET)
Cc: current@freebsd.org
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> As Werner Griessl wrote:
> 
> > rdump in current is very slow, should be ~5 times faster :
> > 
> > Wed Dec 4 09:57:01 1996 start btp1da:system_save to btp1x5:/dev/nrmt0h
> > Wed Dec 4 09:57:01 1996 rewinding tape
> > Wed Dec 4 09:57:07 1996 #1 rdump  /       ... 
> 
> >   DUMP: DUMP: 21409 tape blocks on 1 volumes(s)
> > 
> >   DUMP: finished in 430 seconds, throughput 49 KBytes/sec
> >                                             ^^^^^^^^^^^^^ !!!!!
> 
> I can't confirm this.  What's your blocksize?  What system is the
> remote TCP peer?  Is the tape streaming?
> 

Blocksize is the default (10), remote system is a DEC-alpha 3000/600,
tape is a HP-DAT 35480 with local transfer-rate ~250 kb/sec .


> That's what i get here:
> 
> j@uriah 1523% /sbin/dump 0Bbf 5000000 32 localhost:/dev/rst0 /
> ...
>   DUMP: DUMP: 20154 tape blocks on 1 volumes(s)
>   DUMP: finished in 53 seconds, throughput 380 KBytes/sec
> ...
> j@uriah 1524% /sbin/dump 0Bbf 5000000 32 /dev/rst0 /
> ...
>   DUMP: DUMP: 20154 tape blocks on 1 volumes(s)
>   DUMP: finished in 53 seconds, throughput 380 KBytes/sec
> 
> So of course, it's been the loopback device, but as long as the
> Ethernet card in question can handle 380 KB/s (which is not very
> much), the limiting factor is obviously the tape here.  (It's a
> QIC-2.5GB w/ compression in a Tandberg drive.  The 380 KB/s is a
> normal rate there.)
> 
> -- 
> cheers, J"org
> 
> joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
> Never trust an operating system you don't have sources for. ;-)
>