Re: [Networker] Slow tape positioning on HP LTO 1

Hi Bob,

Decoding 0x1d639 using the 'st(7D)' man page results in the following:

ST_VARIABLE                            0x0001
ST_BSF                                 0x0008
ST_BSR                                 0x0010
ST_LONG_ERASE                          0x0020
ST_KNOWS_EOD                           0x0200
ST_UNLOADABLE                          0x0400
ST_LONG_TIMEOUTS                       0x1000
ST_BUFFERED_WRITES                     0x4000
ST_NO_RECSIZE_LIMIT                    0x8000
ST_MODE_SEL_COMP                      0x10000

     ST_KNOWS_EOD
           If  flag is set,   the device can determine  when  EOD
           (End of Data) has been reached. When this flag is set,
           the st driver uses  fast  file  skipping.   Otherwise,
           file skipping happens one file at a time.

Everything looks to be Ok here.  Anybody else?

Looks like HP LTO2 support was added in 108725-12 so you should be ok there.
BTW, the latest st patch is 108725-14 so you're not too far off.

Have you tried using 'mt' to manually position the tape on specific
records/files and compare the time with legato?  You can use 'mminfo -r
mediafile,mediarec -q ...' to determine the file and record #'s and then 'mt -f
/dev/rmt/? fsr #' and compare the times.  It'd be interesting if the drive
(firmware, st driver, etc) is at fault or Legato.  Just make sure that you're
starting from the beginning of the tape every time.

Regards,
        /\/elson


On Tue, 21 Oct 2003, Bob Payne wrote:

> We also suffer slow tape positioning on recoveries....but not always! We've
> had a call open with Legato for a year now. Our environment...Solaris 8
> (kernel patch 108528-15....OK ,we're a little behind, st patch 108725-13),
> Networker 6.1.2, HP LTO 1 drives in a STK L700e.
> When it takes a while to position, I've noticed that the moving forward of
> files is quick enough, but moving forward records takes the time and it
> reports it in this way....moving forward 1917 records, moving forward 1440
> records, moving forward 1071 records... and so on, the numbers gradually
> getting smaller.
> Snip from st.conf....
> LTO_Ultrium = 1,0x3b,0,0x1d639,4,0x00,0x00,0x00,0x00,3;
> Anybody any thoughts?
> Bob
>
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