Not much difference. Leads me to believe (or suspect, anyway) your performance bottleneck is not the speed of the tape, drive, or connection media.
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Thursday, June 13, 2013 2:23 PM
To: midrange-l@xxxxxxxxxxxx
Subject: LTO4 vs LTO3 speed
I read a chart that says basically:
LTO1:  Up to 40MB/s
LTO2:  Up to 80MB/s
LTO3:  Up to 160MB/s
LTO4:  Up to 240MB/s
LTO5:  Up to 360MB/s
LTO6:  Up to 540MB/s
http://www-304.ibm.com/services/weblectures/dlv/partnerworld/online/ltu29864/mod%208%20ibm%20system%20storage%20tape%20part%203.ppt
And another chart that says the drive makes no difference - it's totally dependent on the interface (we use 280D or 5774)  (something smells rotten about this claim).
http://www-01.ibm.com/support/docview.wss?uid=nas1b69de8ff8246ff2c8625688700566393
This chart says LTO4  Sustained data transfer rate*     Up to 240 Mbps 
compressed*; 120 Mbps native
http://www-03.ibm.com/systems/storage/tape/oem/lto4/specifications.html
Another chart says LTO3 Sustained data transfer rate1:  Up to 60 Mbps native
We have the LTO4 drives in question mounted in a 3573-L4U (aka TS3200) 
http://www-03.ibm.com/systems/storage/tape/ts3200/index.html
Moved from scsi LTO3 to fiber LTO4.
Full system save completed with BRMS:
         03/06/13  06/05/13
          LTO3      LTO4
SAVSYS    00:07     00:07
*IBM      00:06     00:05
*ALLUSR   06:06     06:18
*LINK     00:20     00:19
Another system:
          LTO3      LTO4
SAVSYS    00:18     00:19
*IBM      00:09     00:08
*ALLUSR   02:28     02:34
*LINK     01:30     01:23
Granted, there was a three month time difference in between there. 
Utilization may have changed.
System 1:
Information collected  . . . . . . . . . :   04/11/13  04:00:02
                                                % of         Size in 
Description                                     Disk     1,000,000 bytes
User libraries                                 77.11         3604127.46 
User directories                                1.50           70014.59 
Folders and documents                            .00                .14 
QSYS                                             .10            4481.52 
Other IBM libraries                              .39           18235.97 
Licensed Internal Code                           .11            5182.31 
Temporary space                                  .39           18319.04 
Unused space                                   20.41          953978.86 
System internal objects                          .16            7509.85 
Objects not in a library                         .00                .00 
TOTAL                                         100.17         4681849.74 
Information collected  . . . . . . . . . :   06/13/13  04:00:02
                                                % of         Size in 
Description                                     Disk     1,000,000 bytes
User libraries                                 80.05         3741731.66 
User directories                                1.56           72747.25 
Folders and documents                            .00                .14 
QSYS                                             .10            4596.45 
Other IBM libraries                              .38           17809.87 
Licensed Internal Code                           .11            5199.08 
Temporary space                                  .31           14563.16 
Unused space                                   17.57          821259.54 
System internal objects                          .20            9196.28 
Objects not in a library                         .00                .00 
TOTAL                                         100.28         4687103.43 
System 2:
Information collected  . . . . . . . . . :   04/11/13  04:00:04
                                                % of         Size in 
Description                                     Disk     1,000,000 bytes
User libraries                                 71.73          650784.59 
User directories                                7.37           66912.19 
Folders and documents                            .00              16.75 
QSYS                                             .53            4825.70 
Other IBM libraries                             1.67           15128.99 
Licensed Internal Code                           .54            4913.39 
Temporary space                                 2.45           22214.63 
Unused space                                   14.51          131641.09 
System internal objects                          .98            8872.16 
Objects not in a library                         .00                .01 
TOTAL                                          99.78          905309.50 
Information collected  . . . . . . . . . :   05/30/13  04:00:08
                                                % of         Size in 
Description                                     Disk     1,000,000 bytes
User libraries                                 70.35          638249.19 
User directories                                7.36           66821.73 
Folders and documents                            .00              16.75 
QSYS                                             .77            6973.45 
Other IBM libraries                             1.90           17223.31 
Licensed Internal Code                           .54            4913.39 
Temporary space                                 2.49           22568.05 
Unused space                                   15.78          143215.09 
System internal objects                         1.02            9224.12 
Objects not in a library                         .00                .00 
TOTAL                                         100.21          909205.08 
Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1 Group Dekko Dept 1600 Mail to:  2505 Dekko Drive
          Garrett, IN 46738
Ship to:  Dock 108
          6928N 400E
          Kendallville, IN 46755
http://www.dekko.com
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