Hi TSM-ers! We are using two kind of virtual tape solutions. The old solution is based on the DL4100 from EMC, the new solution is based on the DataDomain form EMC. Because we are using them as a virtual tape server one is also bound to the shortcomings of the tape protocol. If there is some kind of hick-up or congestion during the data transfer, there is no retry, the I/O just fails. I have seen multiple cases where migrations were temporarily saturating the fiber adapters of the Data Domain server or one of the switches in between and this caused an write I/O error. This resulted in a corrupted virtual tape which I think this is strange. If TSM is moving data from the diskpool to a tapepool and this I/O fails and results in an I/O error, why does it delete that data from the diskpool? The data block move should be rolled back is such a case, right? In the case where we are using the DL4100 we are using a primary and a copypool. Most of the times the data which is lost was backed up earlier by the backup stgpool of the diskpool and thus can be restored from the copypool, but in the DataDomain situation we use the DD replication and then the data on the corrupted tapes is gone forever! Thanks for any clarification in advance! Kind regards, Eric van Loon AF/KLM Storage Engineering ******************************************************** For information, services and offers, please visit our web site: http://www.klm.com. This e-mail and any attachment may contain confidential and privileged material intended for the addressee only. If you are not the addressee, you are notified that no part of the e-mail or any attachment may be disclosed, copied or distributed, and that any other action related to this e-mail or attachment is strictly prohibited, and may be unlawful. If you have received this e-mail by error, please notify the sender immediately by return e-mail, and delete this message.
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