Re: [Bacula-users] tape size & speed LTO-1 drive

Arno Lehmann schrieb:
> Hello,
> 
> and welcome!
> 
> 30.11.2009 13:21, Jens Froehlich wrote:
>> Hi bacula-users,
>>
>> I has a problem with my Bacula (3.0.2) installation on OpenSuSE 11.1
>> (32Bit). The LTO-1 tapes are described only a half, nevertheless, it
>> should fit 100 GB on it?
> 
> Depending on the data, yes. Usually, with compression enabled, you'd 
> get more than 100G on each tape.
> 
>> I already succeed different values of the
>> parametres " minimum block size" and "maximum blocksize" tested,
>> unfortunately. If I the tapes with tar describe I reach 100 GB. I also
>> find the writing speed with 6 MB/S a little bit slow?
> 
> Have you run the btape 'test' procedure?
> 
> Do you see any SCSI-related messages in the system's log file?
> 
> And yes, 6MB/s is rather slow for LTO-1, but the bottleneck could be 
> elsewhere.
> 
> To get good speed, you need to do a bit of performance tuning, but 
> let's see the answers for the above questions first :-)
> 
> By the way - I believe Kern will mention performance tuning on his 
> upcoming webinar. A link to regsiter is at 
> http://www.baculasystems.com/eng I don't know what he'll present in 
> detail, though...
> 
> Cheers,
> 
> Arno
> 

- I used new Sony data cardriges with 100/200 GB
- the drive hardwarecompression ist on
- no SCSI errors are to be seen in the log files
- test under Ubuntu 9.10 (server) with bacula 2.2.4 brought the same results
- I have done different tests for the analysis.
- Basically everything seems to be, nevertheless, in order?


Tape Drive - test with the HP Test tool
- Device Performance Test Started on Drive (Ultrium 1-SCSI)
(0.4.0[0-/dev/sg0])
  - Opening Tape Drive 0.4.0[0-/dev/sg0]
  - Successfully opened the Tape Drive /dev/nst0
  - 2147 MB written in 33.6762 seconds at 63.7687 MB/s


hdparm (Hardware RAID5 with SATA Drives)
/dev/sdc1:
 Timing cached reads:   1234 MB in  2.00 seconds = 616.73 MB/sec
 Timing buffered disk reads:  512 MB in  3.01 seconds = 170.11 MB/sec

- the backup reads only from sdc1 (5-10 Gb Files)


write Test with dd
dd if=/dev/zero  of=/dev/nst0 bs=1M count=1000
1000+0 Datensätze ein
1000+0 Datensätze aus
1048576000 Bytes (1,0 GB) kopiert, 16,3772 s, 64,0 MB/s


btape

*test

=== Write, rewind, and re-read test ===

I'm going to write 1000 records and an EOF
then write 1000 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:841 Wrote 1000 blocks of 64412 bytes.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:857 Wrote 1000 blocks of 64412 bytes.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:866 Rewind OK.
1000 blocks re-read correctly.
Got EOF on tape.
1000 blocks re-read correctly.
=== Test Succeeded. End Write, rewind, and re-read test ===


=== Write, rewind, and position test ===

I'm going to write 1000 records and an EOF
then write 1000 records and an EOF, then rewind,
and position to a few blocks and verify that it is correct.

This is an *essential* feature ...

btape: btape.c:953 Wrote 1000 blocks of 64412 bytes.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:969 Wrote 1000 blocks of 64412 bytes.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:978 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 0:999
Block 1000 re-read correctly.
Reposition to file:block 1:0
Block 1001 re-read correctly.
Reposition to file:block 1:600
Block 1601 re-read correctly.
Reposition to file:block 1:999
Block 2000 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:485 Rewound "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:383 open device "LTO-1" (/dev/st0): OK
btape: btape.c:485 Rewound "LTO-1" (/dev/st0)
btape: btape.c:1107 Now moving to end of medium.
btape: btape.c:536 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:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:485 Rewound "LTO-1" (/dev/st0)
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!

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.


=== Write, backup, and re-read test ===

I'm going to write three records and an EOF
then backup over the EOF and re-read the last record.
Bacula does this after writing the last block on the
tape to verify that the block was written correctly.

This is not an *essential* feature ...

btape: btape.c:485 Rewound "LTO-1" (/dev/st0)
btape: btape.c:720 Wrote first record of 64412 bytes.
btape: btape.c:731 Wrote second record of 64412 bytes.
btape: btape.c:742 Wrote third record of 64412 bytes.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:758 Backspaced over EOF OK.
btape: btape.c:763 Backspace record OK.
btape: btape.c:781
Block re-read correct. Test succeeded!
=== End Write, backup, and re-read test ===



=== Forward space files test ===

This test is essential to Bacula.

I'm going to write five files then test forward spacing

btape: btape.c:485 Rewound "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:1587 Wrote one record of 64412 bytes.
btape: btape.c:1589 Wrote block to device.
btape: btape.c:515 Wrote 1 EOF to "LTO-1" (/dev/st0)
btape: btape.c:485 Rewound "LTO-1" (/dev/st0)
btape: btape.c:1321 Now forward spacing 1 file.
We should be in file 1. I am at file 1. This is correct!
btape: btape.c:1333 Now forward spacing 2 files.
We should be in file 3. I am at file 3. This is correct!
btape: btape.c:485 Rewound "LTO-1" (/dev/st0)
btape: btape.c:1346 Now forward spacing 4 files.
We should be in file 4. I am at file 4. This is correct!

btape: btape.c:1364 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.
Slot 1 loaded. I am going to unload it.
3302 Issuing autochanger "unload 1 0" command.
unload status=OK 0
3303 Issuing autochanger "load 1 0" command.
3303 Autochanger "load 1 0" status is OK.
btape: btape.c:383 open device "LTO-1" (/dev/st0): OK
btape: btape.c:1251 Rewound "LTO-1" (/dev/st0)
btape: btape.c:1258 Wrote EOF to "LTO-1" (/dev/st0)

The test autochanger worked!!

-------------------------------------------------------



Jens


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