Eric, The fragmentation occurs because of aggregates. The files within the aggregates expire but the space isn't freed up until all the files in an aggregate expire. Jim Sporer
At 11:14 AM 6/2/2004 +0200, you wrote:
Hi Jim! > I know that this will involve running reclamation on the ATA storage pool but we felt using a DISK device class would waste to much storage because of fragmentation.
Why did you think fragmentation was a waste of space? If a file expires, the space it allocated on a diskpool becomes free space, so it shouldn't be considered wasted. I can imagine that when a lot of little files expire, one gets a lot of fragmented free space, which could have impact on the specific disks performance in the long run. Funny to see that a lot of people (including us) are thinking about SATA storage for their backups. There doesn't seem to be anybody with real hands-on experience however... Kindest regards, Eric van Loon KLM Royal Dutch Airlines
-----Original Message----- From: Jim Sporer [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 01, 2004 21:37 To: [EMAIL PROTECTED] Subject: Re: D2D backup with TSM
We are going to try disk only backups using ATA storage. We've decided to use use a FILE device class for the ATA storage pool and do the backups directly to the ATA storage pool. We will back up the data to a copy storage pool defined on a 3494 tape library. I know that this will involve running reclamation on the ATA storage pool but we felt using a DISK device class would waste to much storage because of fragmentation. Jim Sporer University of Wisconsin
At 10:05 PM 5/28/2004 -0400, you wrote: >We recently had a presentation from EMC. During this presentation >they discussed their new DL700 >virtual tape library. It got people talking about a long >term strategy of moving to a all disk based backup system. So we >started thinking of the pros and cons of how to go about setting up TSM >for a disk based backup system. > >Here are some initial thought on ways to configure TSM for D2D >backups. We would be very interested in your thoughts/comments. I >doubt we are the only people thinking about this topic. > >1)Purchase a very large disk system (ata drives?) and put storage pools on >them. > - use a standard DISK device pool for backups > - how to reclaim space? do you even need to? > - fragmentation problems? > - multiple node access concurrently > - use a FILE device based pool > - single node access per disk file volume > - need to run reclamation > - still stage to disk and migrate to FILE device based pool? > - use a tape copy pool for offsite and backup > - use a offsite disk pool somehow > - iscsi over lan or fc if close enough (enough throughput?) > - other? > - must use client compression to get data compressed > - we mostly don't do this today > >2) Purchase a virtual tape system like the DL700 > (bundle of a EMC Clariion and a FalconStor vts appliance) > - provides compression for data > - appliance is responsible for layout and use of disk space > - can copy a virtual tape to a real physical tape for offsite storage > > >Thanks > >Rick
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