Date: Fri, 5 Sep 2003 11:57:36 +0100 From: Hywel Mallett <hmallett@logicol.co.uk> To: "'freebsd-scsi@freebsd.org'" <freebsd-scsi@freebsd.org> Subject: Very slow tape drive Message-ID: <0B1E2BBC365ED711A6C4000475C90EDA0C619A@LTSPDC1>
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I have a Tandberg SLR60 tape drive, connected to an Adaptec 29160 controller. The drive can backup using dump at around 3MB/s, which is acceptable, if a bit slower than I was expecting. I have a problem though in that I have a large number tapes I need to read the data from. The tapes were written using cpio (on SCO OpenServer), and when trying to read from the tapes using cpio, I only obtain transfer rates of 150KB/s maximum. iostat shows that during both the cpio and the dump, sa0 is managing around ~290 transfers per second, but during the dump each transfer is 10KB, but during the cpio, each dump is 0.5KB. My basic question is do these figures sound normal? Is there a limit of 300 tps on a scsi bus? If so, how could I make the cpio faster? My thoughts included restoring from tape to a file, then using cpio on the file. TIA, Hywel
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