Re: [Bacula-users] bacula compression -- LTO4

2019-01-21 Thread Adam Weremczuk

Hello,

You might be interested in checking this thread: 
https://sourceforge.net/p/bacula/mailman/message/36386670/


A perl script is mentioned there: 
https://github.com/hreinecke/sg3_utils/issues/18 which can provide you 
with e.g. daily reports of raw space remaining on tapes.


Thanks,
Adam


On 21/01/19 08:44, krashoverr...@free.fr wrote:

Hey there!

New question for you, about job compression (on tapes)
I'm running Bacula 7.4.4 server, with a 5.2.6 client (and PG db)

My client has 1.3 To to backup, i'm having an LTO4 drive, meaning 800Go native, 
1.6To compressed, so I've set my pool to have a Maximum Volume Bytes to 1600G
I've read on Bacula docs that for tapes, it's better not to configure 
compression in FileSet, and leave the hardware part do the compression

So what I did (as docs said) is to
- cat /sys/class/scsi_tape/nst0/default_compression which has "1" value
+
root@server:~# tapeinfo -f /dev/nst0
Product Type: Tape Drive
Vendor ID: 'TANDBERG'
Product ID: 'LTO-4 HH'
Revision: 'U519'
Attached Changer API: No
SerialNumber: 'HU1023AMW9'
MinBlock: 1
MaxBlock: 16777215
SCSI ID: 1
SCSI LUN: 0
Ready: yes
BufferedMode: yes
Medium Type: Not Loaded
Density Code: 0x46
BlockSize: 0
DataCompEnabled: yes
DataCompCapable: yes
DataDeCompEnabled: yes
CompType: 0x1
DeCompType: 0x1
BOP: yes
Block Position: 0
Partition 0 Remaining Kbytes: 800226
Partition 0 Size in Kbytes: 800226
ActivePartition: 0
EarlyWarningSize: 0
NumPartitions: 0
MaxPartitions: 0

So the compression seems to be enabled here

The fact is, when I run my backup, only ~1.1 To is used on the tape before 
being Full
+-++---+-+---+--+--+-+--+---+---+-+---+
| mediaid | volumename | volstatus | enabled | volbytes  | volfiles | 
volretention | recycle | slot | inchanger | mediatype | lastwritten | 
expiresin |
+-++---+-+---+--+--+-+--+---+---+-+---+
|   2 |    | Full  |   1 | 1,090,410,854,400 |1,090 |   
 2,592,000 |   1 |0 | 0 | LTO-4 | 2019-01-21 03:25:59 | 
2,569,770 |
+-++---+-+---+--+--+-+--+---+---+-+---+

On the error mail, I can see that
21-Jan 03:26 server-sd JobId 3: End of medium on Volume "x" 
Bytes=1,090,410,854,400 Blocks=16,902,449 at 21-Jan-2019 03:26.
The number of blocks is almost the same than in the tapeinfo command.

Is the "problem" coming from here ?
Anything I can configure to have more that 1.1To used ?

Thank you!

---

Pool {
   Name = QUOT
   Pool Type = Backup
   Volume Retention = 30 days
   Storage = Lecteur_LTO4
   Recycle = yes
   AutoPrune = yes
   RecyclePool = QUOT
   Maximum Volume Bytes = 1600G
}

Storage {
   Name = Lecteur_LTO4
   Password = --
   Address = server
   SDPort = 9103
   Device = Lecteur_LTO4
   Media Type = LTO-4
}

Device {
   Name = Lecteur_LTO4
   Archive Device = /dev/nst0
   Media Type = LTO-4
   LabelMedia = no
   Random Access = no
   AutomaticMount = yes
   RemovableMedia = no
   AlwaysOpen = yes
}


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Re: [Bacula-users] bacula compression -- LTO4

2019-01-21 Thread Tilman Schmidt
On Mon, Jan 21, 2019, at 09:44, krashoverr...@free.fr wrote:
> My client has 1.3 To to backup, i'm having an LTO4 drive, meaning 800Go 
> native, 1.6To compressed, so I've set my pool to have a Maximum Volume 
> Bytes to 1600G

800 GB is the real capacity of an LTO-4 cartridge.
The 1,6 TB "compressed capacity" is purely a marketing number based on the 
unfounded assumption that your data can be compressed to 50%.
Compression depends heavily on the type of data.
Much redundancy (eg. logfiles) -> much compression
Little redundancy (eg. videos) -> little or no compression

> The fact is, when I run my backup, only ~1.1 To is used on the tape 
> before being Full

This confirms that compression is active (otherwise it would be full after 800 
GB) and it is probably all you can get out of compression with your data.

-- 
Tilman Schmidt
til...@imap.cc


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