Hi Alan,
maybe this is an important hint …
I thought btape doesn't use a disk at all. Instead it uses on-the-fly
generation of test data … does it?
If btape uses the configured spool directory I have to take a look at that
point.
> Am 30.11.2015 um 17:00 schrieb Alan Brown <a...@mssl.ucl.ac.uk>:
>
> On 30/11/15 15:32, Christoph Litauer wrote:
>> Andrew,
>>
>> many thanks for this hint. I installed the IBM driver and found the tape
>> drive testing tool itdt, too.
>> Now, using itdt and the new driver there is an improvement:
>> LTO6: 158 MB/s without compression, 177MB/s with compression
>> LTO4: 27 MB/s without compression, 128 MB/s with compression.
>>
>> For LTO6 this is in fact near to the theoretical limit (regarding random
>> data).
>>
>> Using btape with the new driver I still got 153MB/s (with compression) resp.
>> 39 MB/s (random data).
>> Seems as if there is a bottleneck in bacula?
>> My device configuration:
>>
>
> or a bottleneck in your disks.
>
> What is the physical makeup of /var/spool/bacula and how many simultaneous
> sessions have you got using that point?
>
>
>
>> Device {
>> Name = "LTO6-1"
>> Device Type = Tape;
>> Media Type = LTO6
>> Archive Device = /dev/IBMtape0n
>> AutomaticMount = yes;
>> AlwaysOpen = yes;
>> RemovableMedia = yes;
>> RandomAccess = no;
>> Spool Directory = /var/spool/bacula
>> Maximum Spool Size = 300G
>> Maximum File Size = 5G
>> Maximum Block Size = 1m
>> }
>>
>>
>>> Am 28.11.2015 um 08:56 schrieb Andrew Ryder <tire...@shaw.ca>:
>>>
>>> Are you using the IBM Linux tape driver? If not, I'd suggest installing it
>>> vs the generic linux kernel's tape driver.
>>>
>>> http://www-933.ibm.com/support/fixcentral/swg/selectFixes?parent=Tape%2Bdrivers%2Band%2Bsoftware&product=ibm/Storage_Tape/Tape+device+drivers&release=1.0&platform=Linux&function=all
>>>
>>> On 11/27/2015 08:43 AM, Christoph Litauer wrote:
>>>> Dear bacula users,
>>>>
>>>> I recently recognized that my tape drives do not perform as expected.
>>>> Neither while used with bacula nor native with dd. I did many performance
>>>> tests in the meantime but could not figure out the reason. So may I ask in
>>>> this group what typical write speeds you have with your tape drives?
>>>>
>>>> I tested LTO6 (IBM Ultrium HH6) and LTO4 (Ultrium 4-SCSI). Both are part
>>>> of two libraries connected via SAS to a LSI SAS3801E-controller. The host
>>>> system runs SLES12.
>>>> I used btape and dd for writing.
>>>> I figured out the best writing performance with blocksize 512KB (LTO4)
>>>> resp. 2MB (LTO6). Both drives with compression on.
>>>>
>>>> LTO4 best performance (writing zeros): 115 MB/s
>>>> LTO4 worst performance (random data): 71.58 MB/s
>>>>
>>>> LTO6 best performance (zeros): 153 MB/s
>>>> LTO6 worst performance (random): 58 MB/s
>>>>
>>>> Disabling compression does not change the maximum speed. In this case
>>>> writing zeros is the same as writing random date (expected).
>>>>
>>>> According to Wikipedia, theoretical speed should be
>>>> LTO4: 240 resp. 120MB/s
>>>> LTO6: 400 resp. 160MB/s
>>>>
>>>> Any ideas welcome! Thanks in advance!
>>>>
>>>> --
>>>> Kind regards
>>>> Christoph
>>>> _________________________________________
>>>> Christoph Litauer
>>>> Uni Koblenz, Computing Centre, Office A 022
>>>> Postfach 201602, 56016 Koblenz
>>>> Fon: +49 261 287-1311, Fax: -100 1311
>>>>
>>>>
>>>>
>>>>
>>>> ------------------------------------------------------------------------------
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>>>> Bacula-users@lists.sourceforge.net
>>>> https://lists.sourceforge.net/lists/listinfo/bacula-users
>>>>
>>
>> --
>> Freundliche Grüße
>> Christoph Litauer
>> _________________________________________
>> Christoph Litauer
>> Uni Koblenz, Rechenzentrum, Raum A 022
>> Postfach 201602, 56016 Koblenz
>> Fon: +49 261 287-1311, Fax: -100 1311
>>
>>
>>
>>
>>
>> ------------------------------------------------------------------------------
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>
>
>
--
Freundliche Grüße
Christoph Litauer
_________________________________________
Christoph Litauer
Uni Koblenz, Rechenzentrum, Raum A 022
Postfach 201602, 56016 Koblenz
Fon: +49 261 287-1311, Fax: -100 1311
------------------------------------------------------------------------------
Go from Idea to Many App Stores Faster with Intel(R) XDK
Give your users amazing mobile app experiences with Intel(R) XDK.
Use one codebase in this all-in-one HTML5 development environment.
Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs.
http://pubads.g.doubleclick.net/gampad/clk?id=254741911&iu=/4140
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