Duane Schaub wrote: > Yes - but how many users (on a typical ISP) will this support? My > experience with NFS suggests that the number is less than 10000 accounts. > In an early trial, reguardless of load, checking a POP account required > 10-15seconds each. Normally, the same check is instantaneous on local > drives. On the pop server, we normally have 5-10 simultaneous sessions on > POP with about 200 per minute. On NFS, we could only process 100 > connections per minute and the number of simultaneous connections jumps to > 40+. After several minutes, the simultaneous conns started exscalating and > the server crashes at 500. The same machine has no problem on local hard > drive even during heavy spammings.
What hardware, software (versions included), mount options, etc. were you using for the server and clients? Did you do any other NFS (ops/sec) benchmarking on the server. If we don't know basic details like these, we don't have any idea where you're coming from. There are many ways to optimize an NFS server. You have to find the optimum file system size that the NFS server likes to share. Also, it matters how you lay out your shares across arrays of disks. If I have two NFS shares that are the same size, and one of them is comprised of a single 5400 RPM IDE disk, and the other is a RAID 5 array with five 15,000 RPM SCSI disks, it's gonna make a noticeable difference in speed. A nice thing about qmail-ldap, is that it's very easy to split user homedirs across multiple NFS shares. It might be better for your NFS server to share multiple NFS shares (than just one big one) to your mail servers and have the homedirs spread across the shares (based on the optimum share size your NFS server likes, and how your disks and arrays are setup on your server). Also, the mount options you use on the server and clients make a large difference, of course. -- Clint Bullock Network Administrator University of Georgia Office of the Vice President for Research
