Hello Jummo,
Yes, writing an EOF on a tape drive will significantly slow it down. I
am not
sure it actually stops the tape drive. For an LTO-5 I recommend a Maximum
File Size of 5G, but I don't see any serious problem with 10G. The downside
of a larger Maximum File Size is that it takes longer to get to any
given file
for a restore. If you are restoring the whole job then there will be only
one seek to the first file which is not a problem. If you are restoring a
single file or a small number of files, the seek time can be more
important --
it all depends on how fast you want your restores to go. In any case,
Bacula allows you to set a lot of parameters to optimize for
your particular needs.
Best regards,
Kern
On 06/25/2013 09:47 AM, Jummo wrote:
> Hello Kern,
>
> I have set the Maximum File Size to 10 GByte for my LTO5 drive.
> According to the documentation [1], every time the Maximum File Size
> is reach a EOF is written to the tape, the tape will stop. To avoid
> this, the Maximum File Size should set to a higher value.
>
> Until now, I'm fine with the 10 GByte. The write speed is good and all
> restores until now were reasonable fast. Should I decrease the value?
>
> I have restored three jobs (all records were purged from catalog) with
> the
> following bscan command (all jobs where stored on one volume)
>
> bscan -P '<DB password>' -s -m -c /etc/bacula/bacula-sd.conf -v -V
> <Volumename> <Path to tape>
>
> After this I have records for all three jobs, but only one record in
> JobMedia for this tape. A regular tape (without bscan) has serveral
> records in JobMedia. Anything wrong with my bscan command?
>
> Best Regads,
> - Jummo
>
> [1]
> http://www.bacula.org/5.2.x-manuals/en/main/main/Storage_Daemon_Configuratio.html#11807
>
>
>
> On Mon, 24 Jun 2013, Kern Sibbald wrote:
>
>> Hello James,
>>
>> Normally Bacula imports or creates everything from the bscanned
>> Volume that is needed to do proper restores. It can possibly have
>> problems if your original job spanned two volumes and you only
>> bscanned one.
>>
>> The other problem might be in your bacula-sd.conf file. What
>> value do you have for Maximum File Size for the device you are
>> using? The default is 1GB, which is the maximum any linear
>> search should be (on average Bacula will need to read
>> 500MB to find a single file to restore). If you have accidently
>> set this to a very big number thinking it is related to the max
>> size of the Volume, you will be in trouble (well, you will
>> have slow restores). The name is really
>> not the most descriptive one I could have chosen :-(
>>
>> You can check if Bacula is able to seek by listing the
>> JobMedia records for the Job in which the file to be
>> restore was backed up. These are the index records
>> to the media for restore purposes.
>>
>> Best regards,
>> Kern
>>
>
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