SUMMARY: Problem with DLT 4000 tape capacity

From: Bill Bradford <>
Date: Thu Aug 28 2003 - 13:17:32 EDT
I've still not managed to get more than exactly 20G out of the DLT-IV
drive no matter what I try; I've tried using different tape devices,
made sure the drive is set to 20G w/Compression, tried *not* specifying
the tape type/drive in st.conf (as Sol9 natively supports the DLT4K), etc.

However, some of the responses I got may be helpful to someone else.




I've always used                                                                
to do compression with no rewind on DLT-4000 drives.                            

--Ric Anderson


Try using the 'u' specifier instead .. I believe c usually defaults to high     
compression, but  I think the u specifier forces it.                           
ufsdump 0ucf /dev/rmt/0cun /                                                    
ufsdump 0ucf /dev/rmt/0cun /disk                                                

Also, comment out the st.conf entry for the DLT drive and reboot ... Solaris 9  
certainly knows how to talk to that ancient DLT4000 drive. That will rule out  
any typos in the st.conf that might be overiding the correct ones.             

--Buddy Lumpkin


you tried new tapes?  sometimes the mode of the drive is forced by the          
tape itself.  You can manually override the setting by using the                
density select button and keep pressing it until both the 20.0 and              
compress leds are lit.

--Brett Lymn


As far as I know, the DLT4000 is compiled into the actual driver. (see          
DLT4000 on -Is in kernel    
from 2.6)                                                                       
As such, may I suggest try commenting out the DLT4000 entries in st.conf.       
Next do reboot. Then do an mt -f stat /dev/rmt/0 with a cartridge installed     
and ensure it is seeing it a a DLT (not generic SCSI tape dev).Then try         
(Also, the entry                                                                
DLT-data      = 1, 0x38,    0, 0x0D639, 4, 0x80, 0x81, 0x82, 0x83, 2;           
        should have been                                                        
DLT-data      = 1, 0x36,    0, 0x0D639, 4, 0x80, 0x81, 0x82, 0x83, 2;           
According to your links, you "should" be OK as for using the correct device.    
However, on Solaris we normally use /dev/rmt/0cbn directly.                     

--Eugene Schmidt


I'm sure you've gotten your answer by now.  In any case,                        
I believe you need to remove the "b" from the tape device                       
name.  Use /dev/rmt/0cn for the tape device.  
The "b" modifier uses some type of BSD behavior.

--Mark Hargrave


Never used a /dev/nrdlt device.  I don't even have one.  But it looks like it is
+just going to /dev/rmt/0cbn which I think is the problem.                      
I use "c" for compression with my DDS drives but it doesn't turn it on for the  
+DLT (which I found out when I first tried it a couple or three years ago if I  
+remember correctly).  I use "u" on the DLT 7000/8000 but from reading on       
+sunsolve I think "m" is appropriate for the DLT4000: 

DLT 4000                  20 [l]        40 [m]                                  
(other drive info cut)                                                          
2. /dev/rmt density specifiers:                                                 
   DLT 4000:  typically "l" (low) is used for native mode, and "m"              
      (medium) is used to turn on the compression feature on 4000s.             
      This seems to be the convention used at Sun.                              
   DLT 7000:  four density specifiers can be used with this model.              
      l and m will produce the 20 and 40 Gb capacities (like the                
      4000).  However, if "h" is used, the maximum native capacity              
      will be achieved.  To obtain the maximum storage using com-               
      pression, use "u" .                                                       
Anyway you might want to try using /dev/rmt/0mn

--Kenny Raby


bill bradford
austin, texas
sunmanagers mailing list
Received on Thu Aug 28 13:21:20 2003

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