Networker

Re: [Networker] maximum speed to tape using bigasm and /dev/zero

2006-04-27 07:49:49
Subject: Re: [Networker] maximum speed to tape using bigasm and /dev/zero
From: Davina Treiber <DavinaTreiber AT PEEVRO.CO DOT UK>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Thu, 27 Apr 2006 12:47:23 +0100
Jespers, Bart wrote:


if we use Bigasm to test the speed of the link and devices, does this generate 
random data (non-compressable) or data which still can be compressed?
if we use (without networker) the unix "dd" command to send data from /dev/zero 
to tape, this data should be highly compressable?

however using both described methods above, I do not succeed in writing more 
that 55-65MB/s to a IBM LTO2 taped drive comming from a solaris 9 (4CPU, 8GB 
ram) host. the SAN is fully 2 Gbs.
I measured this using the nsrio utility (written by D Stes) which I found on 
the web.

I thought that the max speed of a LT02 was at least 70MB/s and even maybe up to 
140MB/s?

what kind of max speeds have you attained with LT0 1, 2 or 3?


LTO-2 native write speed is 35 MB/s. If you are seeing 55-65 MB/s you're doing fairly well. I have only rarely seen better than that.

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