Hi all,

I wanted to follow up to a number of threads we've already had about 
Bacula performance with LTO-3 and LTO-4 drives.

The lowest-level way to test the drive performance is to use a utility 
provided by the drive manufacturer.  For IBM drives, there is a utility 
called ITDT.

Here are my results from ITDT:

The machine is an IBM x3650 with 2 x Xeon 5150, 8GB RAM.  The controller 
is a SAS1068E:

> 10:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E 
> PCI-Express Fusion-MPT SAS (rev 02)
>     Subsystem: LSI Logic / Symbios Logic Unknown device 3100
>     Flags: bus master, fast devsel, latency 0, IRQ 106
>     I/O ports at 6000 [size=256]
>     Memory at b7ffc000 (64-bit, non-prefetchable) [size=16K]
>     Memory at b7fe0000 (64-bit, non-prefetchable) [size=64K]
>     [virtual] Expansion ROM at b4000000 [disabled] [size=2M]
>     Capabilities: [50] Power Management version 2
>     Capabilities: [68] Express Endpoint IRQ 0
>     Capabilities: [98] Message Signalled Interrupts: 64bit+ Queue=0/0 
> Enable-
>     Capabilities: [b0] MSI-X: Enable- Mask- TabSize=1
>     Capabilities: [100] Advanced Error Reporting
It connects to three LTO-4 SAS drives (in an IBM TS3310) via a 4-to-1 
multiplexer dongle.  0.5m SAS cables.

With the machine idle, tape drives idle, I load a new tape into a drive 
and run itdt and the "full write" test, with "compressible" and 
"incompressible" data:

>                               Block Size  Data Size  Elapsed   Data Rate      
>  
>    Serial No:                    (KB)       (MB)     Time (s)   (MB/s)        
>  
>    +---------------+         +----------+----------+----------+---------+     
>  
>    | 1310023210    |         | 512      | 83923    | 1106.17  | 75.8684 |     
>  
>    +---------------+         | 256      | 83923    | 1122.65  | 74.7544 |     
>  
>                              | 128      | 83923    | 1865.06  | 44.9977 |     
>  
>    C/I: Total KB: Comp.Ratio | 64       | 83923    | 3354.12  | 25.0209 |     
>  
>    +--+----------+---------+ | 32       | 83923    | 6320.65  | 13.2776 |     
>  
>    | C| 445732624| 93.65   | | 16       | 15669    | 2288.65  | 6.84673 |     
>  
>    +--+----------+---------+ | 8        |          |          |         |     
>  
>                              | 4        |          |          |         |     
>  
>            +---------------+ | 2        |          |          |         |     
>  
>    Result: | ABORTED       | | 1        |          |          |         |     
>  
>            +---------------+ +----------+----------+----------+---------+     
>  
>    Code:                      Bin Log:             Text Log:                  
>  
>    +------------------+      +--------------------++--------------------+     
>  
>    | ABORTED BY USER  |      | 1310023210.blz     || 1310023210.txt     |     
>  
>    +------------------+      +--------------------++--------------------+     
>  
>                                                                               
>  
>                                         [R] Return to device list             
>  
> <[Q] Quit | Command > 
>   
>                        Block Size  Data Size    Elapsed    Data Rate          
>    Serial No:              (KB)       (MB)       Time (s)    (MB/s)           
>  
>    +---------------+   +-----------+-----------+-----------+-----------+      
>  
>    | 1310023210    |   | 512       | 83923     | 1109.09   | 75.6683   |      
>  
>    +---------------+   | 256       | 83923     | 1141.26   | 73.5357   |      
>  
>                  +-+   | 128       | 83923     | 1873.68   | 44.7906   |      
>  
>    Comp./Incomp.:|I|   | 64        | 83923     | 3369.68   | 24.9054   |      
>  
>                  +-+   | 32        |           |           |           |      
>  
>                        | 16        |           |           |           |      
>  
>                        | 8         |           |           |           |      
>  
>    Curr. block size:   | 4         |           |           |           |      
>  
>    +----------+        | 2         |           |           |           |      
>  
>    | 32       |(KB)    | 1         |           |           |           |      
>  
>    +----------+        +-----------+-----------+-----------+-----------+      
>  
>                                                                               
>  
>    Remaining (KB):     Progress:              Status:                         
>  
>    +---------------+   +--------------------+ +-------------+                 
>  
>    | 82426120      |   |                    | | FULL WRITE  |  [A] Abort      
>  
>    +---------------+   +--------------------+ +-------------+                 
>  

Doing something like  "dd if=/dev/urandom of=/tmp/test_file_10G bs=1M 
count=10000" then "dd if=/tmp/test_file_10G of=/dev/nst0 bs=X" gives me 
almost exactly the same results.

If the formatting is all screwed up, trying viewing the message as text.

Regards,
Alex

------------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It is the best place to buy or sell services for
just about anything Open Source.
http://p.sf.net/sfu/Xq1LFB
_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users