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Date:      Tue, 26 Jul 2005 23:17:25 -0400
From:      Chuck Swiger <cswiger@mac.com>
To:        ".VWV." <victorvittorivonwiktow@interfree.it>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: certance DAT
Message-ID:  <42E6FCC5.8070309@mac.com>
In-Reply-To: <007b01c59251$925c5ca0$98edfea9@workstation>
References:  <007b01c59251$925c5ca0$98edfea9@workstation>

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[ ...crossposting trimmed... ]

.VWV. wrote:
> I would like to know, if the following product can be used, in order to
> make tape dumps or tape tars with the FreeBSD 4.x.
> 
> http://www.certance.com/products/dds-dat/dat72/CD72LWH-SS

Most probably.  I've a Dell 2850 using a very similiar Seagate DAT72 tape 
drive, which dmesg claims as:

sa0 at amr0 bus 1 target 6 lun 0
sa0: <SEAGATE DAT    DAT72-052 A060> Removable Sequential Access SCSI-3 device

...and this works just fine with dump & tar via /dev/nsa0.  I'd be happier if 
it was a DLT or LTO/Ultrium tape system, though.  Note that I'm only getting 
about 2.5-3 MB/s effective transfer rates to it via:

DUMPARGS="-0acLu -b 64 -C 24 -f /dev/nsa0"

...so it's not exactly super-zippy, either.  Hmm, is it just me, or are the 
following numbers significantly low for a RAID-1 of two 10K RPM U320 SCSI disks...?

/dev/amrd1
         512             # sectorsize
         73274490880     # mediasize in bytes (68G)
         143114240       # mediasize in sectors
         8908            # Cylinders according to firmware.
         255             # Heads according to firmware.
         63              # Sectors according to firmware.

Seek times:
         Full stroke:      250 iter in   1.824059 sec =    7.296 msec
         Half stroke:      250 iter in   1.805398 sec =    7.222 msec
         Quarter stroke:   500 iter in   4.254147 sec =    8.508 msec
         Short forward:    400 iter in   2.821081 sec =    7.053 msec
         Short backward:   400 iter in   2.860203 sec =    7.151 msec
         Seq outer:       2048 iter in   8.821875 sec =    4.308 msec
         Seq inner:       2048 iter in   9.006505 sec =    4.398 msec
Transfer rates:
         outside:       102400 kbytes in   9.242111 sec =    11080 kbytes/sec
         middle:        102400 kbytes in   9.230325 sec =    11094 kbytes/sec
         inside:        102400 kbytes in  10.779231 sec =     9500 kbytes/sec

[ This is running RELENG_5_4... ]

-- 
-Chuck




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