sa(4) driver changes available for test

[Dan Langille]

> On Feb 28, 2015, at 1:47 AM, Kenneth D. Merry <ken at FreeBSD.ORG> wrote:
> 
> On Fri, Feb 27, 2015 at 17:56:42 -0500, Dan Langille wrote:
>> 
>>> On Feb 17, 2015, at 1:36 PM, Kenneth D. Merry <ken at freebsd.org> wrote:
>>> 
>>> On Sat, Feb 14, 2015 at 18:22:43 -0500, Dan Langille wrote:
>>>> 
>>>>> On Feb 13, 2015, at 7:32 PM, Kenneth D. Merry <ken at freebsd.org> wrote:
>>>>> 
>>>>> 
>>>>> I have a fairly large set of changes to the sa(4) driver and mt(1) driver
>>>>> that I'm planning to commit in the near future.
>>>>> 
>>>>> A description of the changes is here and below in this message.
>>>>> 
>>>>> If you have tape hardware and the inclination, I'd appreciate testing and
>>>>> feedback.
>>>> 
>>>> I have a DLT 8000 and an SDLT 220.
>>>> 
>>>> I don't have anything running current, but I have a spare machine which I could use for testing.
>>>> 
>>>> Do you see any value is tests with that hardware? I'd be testing it via Bacula.
>>>> 
>>>> disclosure: I'm the sysutils/bacula-* maintainer and a Bacula committer.
>>>> 
>>> 
>>> Actually, yes.  Bacula is a bit tricky to configure, so your trying it out
>>> would be helpful if you have the time.
>> 
>> I have been unable to test yet.  I've encountered time and hardware issues.
> 
> I know how that goes!  (On both counts.)

Hardware issues fixed.  Now upgrading that zfsroot box from 9.2 to 10.1 RELEASE.

  sudo freebsd-update -r 10.1-RELEASE upgrade

Then I'll grab sources, apply your 10 STABLE patches,  and build world.

> 
>> I may be able to try tomorrow.
> 
> So I have tested building it and it does build at least.  If you're able to
> figure out some of the answers below, that would be great!
> 
>>> 
>>> In looking at the manuals for both the SDLT 220 and the DLT 8000, they both
>>> claim to support long position information for the SCSI READ POSITION
>>> command.
>>> 
>>> You can see what I'm talking about by doing:
>>> 
>>> mt eod
>>> mt status
>>> 
>>> On my DDS-4 tape drive, this shows:
>>> 
>>> # mt -f /dev/nsa3 status
>>> Drive: sa3: <SEAGATE DAT    06240-XXX 8071> Serial Number: HJ00YWY
>>> ---------------------------------
>>> Mode      Density              Blocksize      bpi      Compression
>>> Current:  0x26:DDS-4           1024 bytes     97000    enabled (DCLZ)
>>> ---------------------------------
>>> Current Driver State: at rest.
>>> ---------------------------------
>>> Partition:   0      Calc File Number:  -1     Calc Record Number: -1
>>> Residual:    0  Reported File Number:  -1 Reported Record Number: -1
>>> Flags: None
>>> 
>>> But on an LTO-5, which will give long position information, I get:
>>> 
>>> [root at doc ~]# mt status
>>> Drive: sa0: <IBM ULTRIUM-HH5 E4J1>
>>> ---------------------------------
>>> Mode      Density              Blocksize      bpi      Compression
>>> Current:  0x58:LTO-5           variable       384607   enabled (0x1)
>>> ---------------------------------
>>> Current Driver State: at rest.
>>> ---------------------------------
>>> Partition:   0      Calc File Number:   2     Calc Record Number: -1
>>> Residual:    0  Reported File Number:   2 Reported Record Number: 32373
>>> Flags: None
>>> 
>>> That, in combination with the changes I made to the position information
>>> code in the driver, mean that even the old MTIOCGET ioctl should return an
>>> accurate file number at end of data.  e.g., on the LTO-5:
>>> 
>>> [root at doc ~]# mt ostatus
>>> Mode      Density              Blocksize      bpi      Compression
>>> Current:  0x58:LTO-5           variable       384607   0x1
>>> ---------available modes---------
>>> 0:        0x58:LTO-5           variable       384607   0x1
>>> 1:        0x58:LTO-5           variable       384607   0x1
>>> 2:        0x58:LTO-5           variable       384607   0x1
>>> 3:        0x58:LTO-5           variable       384607   0x1
>>> ---------------------------------
>>> Current Driver State: at rest.
>>> ---------------------------------
>>> File Number: 2  Record Number: -1       Residual Count -1
>>> 
>>> So the thing to try, in addition to just making sure that Bacula continues
>>> to work properly, is to try setting this for the tape drive in
>>> bacula-sd.conf:
>>> 
>>> Hardware End of Medium = yes
>>> 
>>> It looks like the Bacula tape program (btape) has a test mode, and it would
>>> be good to run through the tests on one of the tape drives and see whether
>>> they work, and whether the results are different before and after the
>>> changes.  I'm not sure how to enable the test mode.
>>> 
>>>> I'll let the other Bacula devs know about this.  They deal with the hardware.  I work on PostgreSQL.
>>>> 
>>> 
>>> Thanks!  If there are additional features they would like out of the tape
>>> driver, I'm happy to talk about it.  (Or help if they'd like to use the new
>>> status reporting ioctl, MTIOCEXTGET or any of the other new ioctls.)
>>> 
>>> Ken
>>> -- 
>>> Kenneth Merry
>>> ken at FreeBSD.ORG
>> 
>> ? 
>> Dan Langille
>> http://langille.org/
>> 
>> 
>> 
>> 
>> 
> 
> Ken
> -- 
> Kenneth Merry
> ken at FreeBSD.ORG

— 
Dan Langille
http://langille.org/