Once upon a time, John R Pierce <pierce at hogranch.com> said: > of course, the really tricky problem is implementing an ISCSI > storage infrastructure thats fully redundant and has no single point > of failure. this requires the redundant storage controllers to > have shared write-back cache, fully redundant networking, etc. The > fiberchannel SAN folks had all this down pat 20 years ago, but at an > astronomical price point. Yep. I inherited a home-brew iSCSI SAN with two CentOS servers and a Dell MD3000 SAS storage array. The servers run as a cluster, but you don't get the benefits of specialized hardware. We also have installed a few Dell EqualLogic iSCSI SANs. They do have the specialized hardware, like battery-backed caches and special interconnects between the controllers. They run active/standby, so they can do "port mirroring" between controllers (where if port 1 on the active controller loses link, but port 1 on the standby controller is still up, the active controller can keep talking through the standby controller's port). I like the "build it yourself" approach for lots of things (sometimes too many :) ), but IMHO you just can't reach the same level of HA and performance as a dedicated SAN. -- Chris Adams <linux at cmadams.net>