On Tue May 19 08:25:47 EDT 2009, [email protected] wrote: > What is the most important difference between the two? > Would you please post it to 9fans?
i sent a more complete answer off list (which i've lost). the main difference is that with nupas you don't have to load the entire mailbox into ram if you use mdirs. at coraid we have >3gb of mboxes opened multiple times on a 2gb machine. the largest active mbox is 598mb. also using mdirs has reduced the size of the dump due to mailboxes by 95%. i'm pretty sure there would be very little block sharing in venti, due to how messages move around wrt venti blocks, so the venti savings would be similar. the paper is http://www.quanstro.net/plan9/nupas.pdf. - erik
