Hi Rick! Quite a coincident: I just spoke to DataDomain too! 1) The Dutch guys also confirmed that compressed data is dedupable, but it depends how compression is done. If it's file level compression, you can expect that a copy of that file is similar and thus dedupable. A compressed ntkernel.dll from system A is similar to a compressed ntkernel.dll from system B. 2) and 3) The Dutch DD guys stated that most TSM users with a DataDomain appliance use a storagepool type=disk! Normally you don't want to store your data in a diskpool, because it becomes heavily fragmented overtime, but since the DD appliance does backend defragmentation, front-end fragmentation on you diskpool this will have no negative effect on performance. I found it a very interesting option, since the appliance does in-band and on-the-fly deduplication, compression and defragmentation and has the option to duplicate the de-duplicated data to a remote location. Kind regards, Eric van Loon KLM Royal Dutch Airlines
-----Original Message----- From: ADSM: Dist Stor Manager [mailto:ads...@vm.marist.edu] On Behalf Of Richard Rhodes Sent: maandag 15 juni 2009 15:29 To: ADSM-L@VM.MARIST.EDU Subject: Data Domain - questions from a meeting with DD Hello, The other day we had a meeting with Data Domain - just the normal vendor update about their products. While informative, several comments were made by DD systems that I thought I like your opinions on. (note: we are a all tape shop, and probably will be until the next hardware refresh in several years) Interesting comments DD made: 1) de-dup of compressed data. We told them that much of our backup load comes from Oracle backups that are already compressed via Unix compress utility then pushed to TSM. We asked what effect this would have on de-dup. They said we could expect a 4x-5x de-dup ratio on this compress data. I had always thought that compressed data would not de-dup. 2) NFS mounted storage pools. They said that the vast majority of their installations, including TSM installations, use NFS (some OpenStorage for NetBackup, and a little CIFS) for backups to disk. In other words, VTL emulation is a very small percentage of their installations. If you have DD hdwr, are you using NFS or file devices, or, a vtl interface? Is anyone using NFS for a storage pool? 3) DD reclaim of scratch tapes I asked about when/how DD will reclaim no longer used space. In other words, when a scratch tape passed reuse-delay. He said that DD had some kind of interface to backup softw such that it knows when data is no longer needed and reclaimes that space. I know TSM v5.5 has a feature to clear a vol when no longer used with a vtl, but DD was saying they had a special interface to accomplish this. Does DD have a special interface to TSM? Thanks Rick ----------------------------------------- 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. ********************************************************************** 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. Koninklijke Luchtvaart Maatschappij NV (KLM), its subsidiaries and/or its employees shall not be liable for the incorrect or incomplete transmission of this e-mail or any attachments, nor responsible for any delay in receipt. Koninklijke Luchtvaart Maatschappij N.V. (also known as KLM Royal Dutch Airlines) is registered in Amstelveen, The Netherlands, with registered number 33014286 **********************************************************************
