SCSI reservation conflict on tape device between NDMP storage unit and media server storage unit.

Problem

Although backups are working successfully, some SCSI reservation conflict messages are being logged in the /var/adm/messages file on a Solaris media server.  What is the root cause of these messages ?

Error Message

Wed Aug 25 21:48:07 SGT last message repeated 3 times
Wed Aug 25 21:48:08 SGT [XXX-Filer01: tapemc.device.resvConfl:error]: Reservation conflict on tape device sg_xxx_xxxx01:29.126L5.
Wed Aug 25 21:48:08 SGT last message repeated 2 times
Wed Aug 25 21:48:27 SGT [XXX-Filer01: tapemc.device.resvConfl:error]: Reservation conflict on tape device sg_xxx_xxxx01:29.126L4. 

Cause

The media server is logging SCSI reservation conflict messages due to a conflict when trying to acquire a SCSI reservation on a shared device. The cause of the reservation conflict was because the Filer had SCSI persistent reservation configured but the Media server has SCSI-2 reserve/release configured. 

Solution

When using SSO, shared devices require the same level of SCSI reservation. The default SCSI reservation configured within Netbackup is SCSI-2 reserve/release. The solution is to either configure SCSI-2 reserve/release on the Filer or to configure persistent reservation within Netbackup.

ONTAP 7.1 release supports SCSI Reserve/Release commands for the Shared Storage Option of Veritas VERITAS NetBackup 6, which allows users to dynamically share tape devices with NDMP backup policies. To enable the SCSI Reserve/Release commands, set the "tape.reservations" option to 'scsi'  . 

Open command window on the filer

Filer> options tape.reservations scsi

Valid values are off, scsi, or persistent. For more information, see na_options(1) man page.

Applies To

Media Server Solaris 10 Netbackup 6.5.5 using SSO (Shared Storage Option).
Netapp NDMP Filer Ontap 7.2.1
I2K library fibre attached

The I2k library tape devices are presented to a Solaris media server and a Netapp NDMP filer.