sa(4) driver changes available for test
Dan Langille
dan at langille.org
Mon Mar 2 00:41:09 UTC 2015
> On Mar 1, 2015, at 7:31 PM, Kenneth D. Merry <ken at FreeBSD.ORG> wrote:
>
> On Sun, Mar 01, 2015 at 19:15:05 -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.
>>>
>>> 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 have this in /usr/local/etc/bacula/bacula-sd.conf
>>
>> Device {
>> Name = DLT
>> Description = "QUANTUM DLT7000 1624"
>> Media Type = DLT
>> Archive Device = /dev/nsa1
>>
>> Autochanger = YES
>> Drive Index = 0
>>
>> Offline On Unmount = no
>> Hardware End of Medium = yes
>> BSF at EOM = yes
>> Backward Space Record = no
>> Fast Forward Space File = no
>> TWO EOF = yes
>> }
>>
>> FYI, http://www.freebsddiary.org/digital-tl891.php (from 2006) has a btape test on this same model.
>>
>> Here's the test I ran tonight:
>>
>> [root at cuppy:/usr/home/dan] # btape -c /usr/local/etc/bacula/bacula-sd.conf /dev/nsa1
>> Tape block granularity is 1024 bytes.
>> btape: butil.c:287-0 Using device: "/dev/nsa1" for writing.
>> btape: btape.c:469-0 open device "DLT" (/dev/nsa1): OK
>> *test
>>
>> === Write, rewind, and re-read test ===
>>
>> I'm going to write 10000 records and an EOF
>> then write 10000 records and an EOF, then rewind,
>> and re-read the data to verify that it is correct.
>>
>> This is an *essential* feature ...
>>
>> btape: btape.c:1152-0 Wrote 10000 blocks of 64412 bytes.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1168-0 Wrote 10000 blocks of 64412 bytes.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1210-0 Rewind OK.
>> 10000 blocks re-read correctly.
>> Got EOF on tape.
>> 10000 blocks re-read correctly.
>> === Test Succeeded. End Write, rewind, and re-read test ===
>>
>> btape: btape.c:1277-0 Block position test
>> btape: btape.c:1289-0 Rewind OK.
>> Reposition to file:block 0:4
>> Block 5 re-read correctly.
>> Reposition to file:block 0:200
>> Block 201 re-read correctly.
>> Reposition to file:block 0:9999
>> Block 10000 re-read correctly.
>> Reposition to file:block 1:0
>> Block 10001 re-read correctly.
>> Reposition to file:block 1:600
>> Block 10601 re-read correctly.
>> Reposition to file:block 1:9999
>> Block 20000 re-read correctly.
>> === Test Succeeded. End Write, rewind, and re-read test ===
>>
>>
>>
>> === Append files test ===
>>
>> This test is essential to Bacula.
>>
>> I'm going to write one record in file 0,
>> two records in file 1,
>> and three records in file 2
>>
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:469-0 open device "DLT" (/dev/nsa1): OK
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1420-0 Now moving to end of medium.
>
> This is the critical piece. The test moves the tape to the end of the
> medium. With hardware position information, you can tell what filemark
> you're on. Without it, you can't.
>
>> btape: btape.c:622-0 tape_dev.c:345 ioctl MTIOCGET error on "DLT" (/dev/nsa1). ERR=No error: 0.
>> We should be in file 3. I am at file 0. This is NOT correct!!!!
>>
>> Append test failed. Attempting again.
>> Setting "Hardware End of Medium = no
>> and "Fast Forward Space File = no
>> and retrying append test.
>
> This is not surprsing, given that the drive doesn't support long read
> position data. (It's a SCSI-2 device.) So that means that Bacula will
> need to do it manually.
Yes, I have nothing newer than SCSI-2. Even my SDLT is SCSI-2 but that
tape library is hooked up to a different computer and was doing backups today.
> === Append files test ===
>>
>> This test is essential to Bacula.
>>
>> I'm going to write one record in file 0,
>> two records in file 1,
>> and three records in file 2
>>
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:469-0 open device "DLT" (/dev/nsa1): OK
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1420-0 Now moving to end of medium.
>> btape: btape.c:625-0 Moved to end of medium.
>> We should be in file 3. I am at file 3. This is correct!
>>
>> Now the important part, I am going to attempt to append to the tape.
>>
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> Done appending, there should be no I/O errors
>>
>> Doing Bacula scan of blocks:
>> 1 block of 64448 bytes in file 1
>> End of File mark.
>> 2 blocks of 64448 bytes in file 2
>> End of File mark.
>> 3 blocks of 64448 bytes in file 3
>> End of File mark.
>> 1 block of 64448 bytes in file 4
>> End of File mark.
>> Total files=4, blocks=7, bytes = 451,136
>> End scanning the tape.
>> We should be in file 4. I am at file 4. This is correct!
>>
>>
>> It looks like the test worked this time, please add:
>>
>> Hardware End of Medium = No
>>
>> Fast Forward Space File = No
>> to your Device resource in the Storage conf file.
>>
>> The above Bacula scan should have output identical to what follows.
>> Please double check it ...
>> === Sample correct output ===
>> 1 block of 64448 bytes in file 1
>> End of File mark.
>> 2 blocks of 64448 bytes in file 2
>> End of File mark.
>> 3 blocks of 64448 bytes in file 3
>> End of File mark.
>> 1 block of 64448 bytes in file 4
>> End of File mark.
>> Total files=4, blocks=7, bytes = 451,136
>> === End sample correct output ===
>>
>> If the above scan output is not identical to the
>> sample output, you MUST correct the problem
>> or Bacula will not be able to write multiple Jobs to
>> the tape.
>>
>> Skipping read backwards test because BSR turned off.
>>
>>
>> === Forward space files test ===
>>
>> This test is essential to Bacula.
>>
>> I'm going to write five files then test forward spacing
>>
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:1907-0 Wrote one record of 64412 bytes.
>> btape: btape.c:1909-0 Wrote block to device.
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:604-0 Wrote 1 EOF to "DLT" (/dev/nsa1)
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1634-0 Now forward spacing 1 file.
>> We should be in file 1. I am at file 1. This is correct!
>> btape: btape.c:1646-0 Now forward spacing 2 files.
>> We should be in file 3. I am at file 3. This is correct!
>> btape: btape.c:574-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1659-0 Now forward spacing 4 files.
>> We should be in file 4. I am at file 4. This is correct!
>>
>> btape: btape.c:1677-0 Now forward spacing 1 more file.
>> We should be in file 5. I am at file 5. This is correct!
>>
>> === End Forward space files test ===
>>
>>
>> Ah, I see you have an autochanger configured.
>> To test the autochanger you must have a blank tape
>> that I can write on in Slot 1.
>>
>> Do you wish to continue with the Autochanger test? (y/n): y
>>
>>
>> === Autochanger test ===
>>
>> 3301 Issuing autochanger "loaded" command.
>> Nothing loaded in the drive. OK.
>> 3303 Issuing autochanger "load 1 0" command.
>> 3303 Autochanger "load 1 0" status is OK.
>> btape: btape.c:469-0 open device "DLT" (/dev/nsa1): OK
>> btape: btape.c:1564-0 Rewound "DLT" (/dev/nsa1)
>> btape: btape.c:1571-0 Wrote EOF to "DLT" (/dev/nsa1)
>>
>> The test autochanger worked!!
>
> Great, thanks for running the test! Looks like things are working as well
> as they were before.
>
>>>
>>>> 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.)
>>
>> Errors are interesting to me. Especially corrected errors. They are a good indicator of tape quality.
>>
>
> Yes. At least on modern drives, there is a good bit available in the log
> pages. You can try seeing what logs your drive supports by installing the
> sg3_utils package and running 'sg_logs sa1 --all'.
>
> Given the large amount of data available on some drives, and the difficulty
> distilling it down to a clear good/bad, I probably won't stick that in the
> 'mt status' output.
>
> But you can certainly take a look at it and have an idea of whether your
> particular tape/drive are experiencing issues.
That's a lot of output: https://gist.github.com/dlangille/0e15a7fbf7acab56fd32
I will run some Bacula jobs soon. I'm still setting up config files.
—
Dan Langille
http://langille.org/
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