On 06/28/10 7:53 PM, Emmanuel Noobadmin wrote: > The only problem is their HA is commercial only and costs more than > the entire hardware budget I've got for this. Crucially, it relies on > a failover/heartbeat kind of arrangement. According to some sources, > the failover delay of a few seconds will cause certain services/apps > to fail/lock up. Not an issue for the immediate need but will be a > major no no for the other project I have in the pipeline. > > Which was why I was thinking of MD raid 1 on the application server > site: no failover delay if one of the data server fails to respond to > respond in time. > ISCSI gets REAL sketchy on network failures. it takes at least several TCP timeouts before it gives up and returns an error. I do hope both storage servers have ECC so you're not mirroring a soft bit error at an inopportune time (Solaris ZFS would cope gracefully with this, but likes iscsi timeouts even less than dmraid)