We are adding a new NAS to our environment, and I have a question regarding space required for backups. Currently, I have about 10TB on a SAN connected via fiber to 3 ESXi hosts and our Server 2008 backup exec server. I have roughly 9TB of space on the BE server, which is sufficient for weekly full and daily diffs of the VMs on the SAN.
The new NAS I am putting in (or additional tray of disks to the SAN) will be 40TB of data. This is the most I have ever backed up, and I am honestly not sure how much space I need to add to the BE server. The general plan is the 15TB will be read-only archive, the rest active data changing daily. Once a file has not been modified for 3 months, it will be moved to the archive.
SO, theoretically I will be backing the archive up straight to tape only when data is added to it. The other 25TB will require a weekly full and daily diff/inc. Does anyone have a suggestion on how I should quote storage for this? I am initially thinking a DAS with 10-12 disks 4TB each.