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Title
Attempted to write past end of media error on a VTL that resides on a DataDomain. -
Description
When running NDMP backups from the customers Netapp Filer (ONTAP 7.3.2P6), the jobs fail when they fill the first VTL media:
Error 2010/05/10 17:45:29 928 Media BACKUP1 BACKUP1\1.1.1.1\backup\coniston1a\vtl2\vtl2\drives\1: had media error
With sub text:DEVCOMMO:07628 59 0 164528 Before at 8:99941
MEDWRITE:07628 184 0 164528 Device write data out: EOM WARNING
DEVMGR :07628 107 0 164528 Space Remaining (BEGIN)
DEVMGR :07628 108 0 164528 Total data written 262144
DEVMGR :07628 109 0 164528 Segment Length left 26197622784
DEVMGR :07628 110 0 164528 Old segment estimate 0
DEVMGR :07628 784 0 164528 At EOM
DEVMGR :07628 571 0 164528 Space Left 0
DEVMGR :07628 245 3 164528 New estimate : 262144
DEVMGR :07628 246 3 164528 Existing estimate: 0
DEVMGR :07628 117 0 164528 New space left estimate is bigger than last estimate
DEVMGR :07628 99 0 164528 Send Space Left (BEGIN)
DEVMGR :07628 239 3 164528 Space estimate: segment remaining 0
DEVMGR :07628 240 3 164528 segment length 262144
DEVMGR :07628 241 3 164528 current position 262144
DEVMGR :07628 242 3 164528 data written 262144
DEVMGR :07628 243 3 164528 offset 0
DEVMGR :07628 102 0 164528 Send Space Left (END)
DEVMGR :07628 123 0 164528 Space Remaining (END)
DEVDISK :07628 43 0 164528 Get Position
DEVCOMMO:07628 60 0 164528 After at 8:99942
DEVDISK :07628 43 0 164528 Get Position
DEVCOMMO:07628 59 0 164528 Before at 8:99942
DEVCOMMO:07628 2 0 164528 ----->>> PAUSED <<<-----
DEVDISK :07628 43 0 164528 Get Position
DEVCOMMO:07628 60 0 164528 After at 8:99942
DEVMOVER:07628 643 0 164528 Paused: reason 1 seek position 0
DISKFILE:07628 100 0 164528 \1.1.1.1\backup\coniston1a\vtl2\vtl2\drives\1 bIsProtected = FALSE
DEVDISK :07628 43 0 164528 Get Position
DEVMOVER:07628 618 0 164528 Paused
DEVMOVER:07628 619 0 164528 Unsupported = 0x70
DEVMOVER:07628 620 0 164528 Flags = 0x8
DEVMOVER:07628 621 0 164528 File Number = 8
DEVMOVER:07628 622 0 164528 Soft Errors = 0
DEVMOVER:07628 623 0 164528 Block Size = 262144
DEVMOVER:07628 624 0 164528 Block Number = 99942
DEVMOVER:07628 607 0 164528 Paused
DEVMOVER:07628 608 0 164528 State 3
DEVMOVER:07628 800 0 164528 Mode 0
DEVMOVER:07628 609 0 164528 Pause Reason 1
DEVMOVER:07628 610 0 164528 Halt Reason 0
DEVMOVER:07628 611 0 164528 Record Size 262144
DEVMOVER:07628 612 0 164528 Record Number 99941
DEVMOVER:07628 613 0 164528 Bytes Moved 26198933504
DEVMOVER:07628 614 0 164528 Seek Position 0
DEVMOVER:07628 615 0 164528 Bytes Left to Read 0
DEVMOVER:07628 616 0 164528 Window Offset 0
DEVMOVER:07628 617 0 164528 Window Length 18446744073709551615
DEVMOVER:07628 646 0 164528 Media at record 99942 written 26199195648
DEVMOVER:07628 757 0 164529 bEndSegment = TRUE
MEDWRITE:07628 152 0 164529 Close Write Data Out (BEGIN)
DEVDISK :07628 95 0 164529 Close Write Segment
DISKFILE:07628 121 0 164529 Attempted to write past end of media
MEDWRITE:07628 276 0 164529 Failed to close write segment -
Resolution
As you can see from the logs above, the End Of Media (EOM) is fluctuating and therefore overshoots the end of the media and fails. These fluctuating EOM issue is a known issue and is to do with the VTL Compression Software and if this feature is enabled, then these errors would happen.
The customer had this feature already disabled and this issue is only happening when spanning VTL media.
You will need to set the following on all VTL Drives, by right clicking the VTL Drives' "Configure," “Configuration tab.“ Set the "End of media warning" from 0 to 1. If this doesn't work, then increase the value by 1 until you reach 10. This will allow for some additional space at the end of media and then won't over shoot it.
You may also have to set the Media Block Size under the VTL Drives - Configure - Configuration tab to either 32 or 64. -
Additional Information
BakBone SFDC Solution Number: 00005633