Hi Richard, We backup our Oracle database via two channels so the data is split onto two different tapes. Therefore we can use two channel restores.
Four channel restore doesn't make any sense as the other two extra channels can't mount the tapes which are already in use by the first two restore sessions. Hope this helps Best Regards, Oscar UNIX/TSM/SAN Administrator | ING Direct 410 Thames Valley Park Drive, Reading, Berkshire, RG6 1RH Tel: 0118 938 1990 l Email: oscar.kolste...@ingdirect.co.uk -----Original Message----- From: ADSM: Dist Stor Manager [mailto:ads...@vm.marist.edu] On Behalf Of Richard Rhodes Sent: 07 January 2009 14:16 To: ADSM-L@VM.MARIST.EDU Subject: [ADSM-L] TDP for Oracle - multi channel restore Hello, We are still fairly new to RMAN/TDPO backups, and trying to understand behavior. We have one 10tb database that performs RMAN backups to TSM using one tape drive (one channel). Oracle datafiles are interleaved (not sure of the level). We are now performing a full restore on this database. The dba allocated 4 channels for the restore (4 tape drives). We started getting session timeouts. It looks like Oracle was asking for aggregate files on different channels that in TSM are on the same tape. This caused tape contention and session timeouts. The restore was stopped and changed to a single channel. I've been trying to find info on issues/limitations around RMAN/TDPO restores with multiple channels, but not finding much info. Questions: 1) Does the number of channels on a restore have to be the same or less than the number used for the backup? 2) Is it even possible to do multi channel restores? In other words, does RMAN have knowledge of the tape volumes so as to not cause tape contention across channels? ----------------------------------------- The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message. ************************************************************************ ******************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by an antivirus scanner for the presence of computer viruses. ING Direct NV is a limited liability company incorporated in The Netherlands. Registered in England & Wales, Branch Ref BR7357, 410 Thames Valley Park Drive, Reading, Berkshire, RG6 1RH. ************************************************************************ ******************************************** --------------------------------------------------------------------------------------------------------------- ATTENTION: The information in this electronic mail message is private and confidential, and only intended for the addressee. Should you receive this message by mistake, you are hereby notified that any disclosure, reproduction, distribution or use of this message is strictly prohibited. Please inform the sender by reply transmission and delete the message without copying or opening it. Messages and attachments are scanned for all viruses known. If this message contains password-protected or encrypted attachments, the files have NOT been scanned for viruses by the ING mail domain. Always scan attachments before opening them. ING Direct NV is limited liability company incorporated in The Netherlands. Registered in England & Wales, Branch Ref BR7357, 410 Thames Valley Park Drive, Reading, Berkshire, RG6 1RH. ---------------------------------------------------------------------------------------------------------------
