Richard,

Here is something to think about:

What Timothy is doing is essentially tape-to-tape data movement for one node, 
with that node's data likely scattered to some degree across the input tape.  
This means that there will be some tape repositioning needed to read the input 
tape.  If the output was to disk, it is likely that the input tape could stay 
pretty much in streaming mode.  However, with the output being directed to 
tape, IMHO it is much more likely that between the input tape repositions and 
not being able to keep the output tape in streaming mode, the combination will 
likely result in an inordinate amount of backhitching.  I don't think this is a 
hardware error, so much as a tape technology limitation.  We get around this by 
using serial disk as an interim step, which allows the whole process to run 
more quickly (because there is less overall backhitching).

..Paul


At 08:34 AM 7/8/2011, Richard Sims wrote:
>On Jul 8, 2011, at 7:57 AM, Hughes, Timothy wrote:
>
>> Yes, We are doing Server-to-tape exports. I did notice a couple times long 
>> input tape mounts on the destination TSM SERVER one was around 6,000 seconds 
>> another around 14,000 seconds and another 17,000 seconds.
>
>Export/Import operations are, per the Admin Guide manual topic "Preemption of 
>client or server operations", high priority, which would pre-empt lower 
>priority operations in order to get a tape mount started.  If prompt 
>allocation of tape drives is being reflected in your Activity Log, but then 
>tape mount and positioning is taking an inordinate amount of time, that would 
>suggest hardware issues with tapes or drives. If non-Export operations do not 
>exhibit such delays, then something else is going on, where analysis of the 
>Activity Log and operating system logs may reveal factors.  If no cause is 
>evident, contacting TSM Support would be in order.
>
>    Richard Sims


--
Paul Zarnowski                            Ph: 607-255-4757
Manager, Storage Services                 Fx: 607-255-8521
719 Rhodes Hall, Ithaca, NY 14853-3801    Em: psz1 AT cornell DOT edu