certance DAT
Chuck Swiger
cswiger at mac.com
Wed Jul 27 03:17:39 GMT 2005
[ ...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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