Dell power vault - (read NX1950) limitations - only 4tb of raid5 space - better off to look at a fibre chanel solution
now i'll probably get flamed for this.. but 2 x win2k3r2x64 servers running mscs and some custom scripting to act as the NAS servers.
1-2 x cpanel servers (cpanel admin/client use ONLY)
1-8 webservers - httpd(webmail) & dns ONLY
1-8 smtp/pop3 servers
2 mysql servers
2 x front end load balancers - commerical solution or freebie (ultramonkey /ipvs) or cisco / barracuda(what we use)
Create NFS mounts on the windows boxes. Use SFU & some custom scripts for user creation. Modify wwwacct a bit to accomodate - check into NIS with SFU
Install base os's on the other servers
set up nfs and fstab structure
buy 2 cpanel licences
install cpanel x 2 (or x1)
custom compile apache2.2 for the webservers + modify php source so that mysql connects - connect to the mysql failover IP - rather than localhost use cband instead of bandmin -
install exim + courier on mail servers. - Use symlinks or scp & cron to copy files
set up mysql as a failover clusteri.e primary slave with identical config - with data and config stored on nas.. no need for slave/master just a simple heartbeat config and a few scripts.
Lots of testing, quite a few custom mods to cpanel - lots of chattr +i'ng to stop upcp blowing away configs, some custom vb scripts to pull quotas etc from windows (yes you could use linux, but seriously, clustering in linux, and clustered fs's suck unless you want to pay bulk$$$ for a decent solution
thats pretty much all you need to know about cpanel clustering.. fill in the blanks for yourself and extpect minimum 4 weeks full time building the system and debugging and making small changes..
skills required
perl scripter
linux admin
windows skillset
vb/asp/iis/clustering
clustering knowledge
lots of coffee
lots of patience
ip networking skillset
Have fun
*edit*
For reference, drbd, gfs. afs, coda all = BS slow...
I was lucky to get 70mb/s throughput... Windows NFS - I maxed out the dual path nics in the machines - 1500mbs (read: mbs, NOT MBs)
Also, the above is usless, unless you have a redudant core capable of failing over. In our case, we have 2 x 6500's(hsrp) + 4 x 24 port gb switches with dual path fibre uplinks into the cisco's, the c6500's handle bgp routing to multiple upstream providers.. We can take 2 of the switches and 1 cisco out of service and everything keeps running.
