1) When you set COLLOCATION ON for a storage pool, nothing happens to existing data. COLLOCATION just changes the rules for TSM selecting output tapes. (actually any sequential output volumes) When migration starts to a sequential pool, by default TSM will chose a tape in the pool that is already in FILLING status. If there isn't one, it chooses a scratch. If collocation is on by NODE for a storage pool, TSM will choose a tape in the pool that is already in FILLING status and already has data for the client node whose data is being migrated, if there is one. If there isn't, it chooses a scratch. If there isn't a scratch available, it chooses a tape that is in FILLING status. Extrapolate for yourself what happens when collocation is on by FILESPACE, by GROUP, etc. Same thing happens for RECLAMATION or for MOVE DATA - any time TSM has to select a tape for OUTPUT. So you can turn collocation on, turn it back off, turn it on again, etc-- All you are affecting is the choice of an output tape. 2) Over time, reclamation will cause the data to gradually become more collocated, since data is written to new tapes via the new rules. IF you want to force it to happen, you can run MOVE DATA or MOVE NODEDATA commands to force existing volumes to be rewritten, with collocation on.
________________________________ From: ADSM: Dist Stor Manager on behalf of William Kyndt Sent: Fri 4/20/2007 11:16 AM To: ADSM-L@VM.MARIST.EDU Subject: Collocation Hi, We currently use Tivoli Version 5.3.2 and wish to implement collocation for some of our servers. I have a few questions regarding enabling collocation and would appreciate any advice anyone is able to share. 1. When enabling collocation for a group of servers, does a full backup of the servers occur to group the data on as few volumes as possible followed by incremental backups? Or do incremental backups still occur as normal and are simply grouped on pre defined volumes? 2. Is there a way to collocate data already backed up onto fewer volumes? We use GroupWise as our e-mail system which comprises of thousands of files and directories, when performing a full system restore which can be in excess of 500 GB this can take some time because of all the tape mounts taking place. We are hoping that by collocating this data onto fewer tapes this will reduce the length of time taken to complete a complete restore in the event of a disaster. Any advice surrounding collocation would be greatly appreciated. Kind regards, William ********************************************************************** The Miller Group Limited Registered in Scotland - SC018135 Miller Homes Limited Registered in Scotland - SC255429 Miller Construction (UK) Limited Registered in Scotland - SC209666 Miller Developments Limited Registered in Scotland - SC178108 2 Lochside View Edinburgh Park Edinburgh EH12 9DH Disclaimer: The Information in this e-mail is confidential and for use by the addressee(s) only. It may also be privileged. If you are not the intended recipient please notify us immediately on +44 (0) 870 336 5060 and delete the message from your computer: you may not copy or forward it, or use or disclose its contents to any other person. We do not accept any liability or responsibility for: (1) changes made to this email after it was sent, or (2) viruses transmitted through this email or any attachment.
