Date: Thu, 2 May 1996 13:31:49 -0700 (PDT) From: "JULIAN Elischer" <julian@ref.tfs.com> To: wilko@yedi.iaf.nl (Wilko Bulte) Cc: FreeBSD-hackers@FreeBSD.org Subject: Re: using DLT drive on FreeBSD Message-ID: <199605022031.NAA10015@ref.tfs.com> In-Reply-To: <199605021801.UAA01622@yedi.iaf.nl> from "Wilko Bulte" at May 2, 96 08:01:19 pm
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> > Hi there > > First of all, the drive works just fine on my Asus P90/NCR810 > The main problem is that I cannot set the buffersize used by 'dump' > to a high enough value to keep the tape streaming. These puppies need > 1.3 - 2.5 Mbyte/second to keep streaming OK. The actual required rate is > dependent on how good the data compresses. An experiment @ work with a > Sun Sparc20 revealed a 1.9Mbyte/second transferrate while dumping the > /usr Solaris filesystem. Side note: I had to put the drive on a seperate > SCSIbus/adapter to make this work. try piping your data throughgh 'team' (in the packages..) it should up your throughput by allowing concurrent file-system reads and tape writes.. > > I think the 2.1R limit is 32kbytes. In the recent past there was a > discussion about this on this list (in relation to DAT drives??). Didn't > pay too much attention at the time because I did not have the drive then. > Is there any way to increase this value (seem to remember there was not.?) Actually it's 64Kbytes > > It is of course also possible that the HD & tape being on the same NCR810 > are hurting the streaming operation. no, that should be ok.. > > NB looks like I also have to hack a bit into 'mt' to allow the density/ > compression settings to work. WIll dig up the device spec to see what > that has to say > > Comments? > > Wilko > _ __________________________________________________________________________ > | / o / / _ Wilko Bulte email: wilko@yedi.iaf.nl > |/|/ / / /( (_) Private FreeBSD site - Arnhem - The Netherlands > -------------------------------------------------------------------------------- >
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