On Wed, Nov 30, 2011 at 8:16 PM, Allen S. Rout <[email protected]> wrote: > How many tapes do you have? Now envision _all_ of them being mounted > for any restore, even a relatively small one. That's the end state of > colloc=no: to a first approximation, every node, every filespace, > every directory, is smeared across a maximum number of tapes, with no > tendency to re-group data which is predictably related
Mounting 1000 tapes to restore 20G would not be good. I agree. > Collocation is about paying, in unused tape space, for efficient > restores; I'd suggest you view that as a bargain, not a burden. Having our tapes extremely under utilized to achieve some kind of acceptable performance is a burden. I only see using disk as a solution here. At least for incrementals. We don't have the time to do extensive micro management to reach a compromise between unacceptable tape utilization and unacceptable restore times. Hans Chr.
