| In principal this is true. However, cec is not so reliable of a connection. It is NOT TCP. I have little information about how resilient the protocol is, however, in a unit we have with a bad disk, I've had the cec connection spontaneously drop mid-command. I'm sure they're working to fix this, but it doesn't bode well for something as critical as fencing. I'm also unclear on whether a dropped connection generates a non-zero exit code (i.e. is even detectable). Also, on APCs, the fence_apc script has the benefit that the APC switches do not allow more than one concurrent telnet connection, which effectively serializes fence requests. With the cec, not so much. Also, this fences the entire Coraid device in a way that must be manually cleared if it gets left masked. This is a real possibility where multiple nodes are racing to fence each other--especially on multiple Coraid shelfs (as it must be done per shelf). Since we use our Coraids for non-GFS boot volumes as well, this is also problematic for us, since a stale mask entry keeps us from booting. It's really not so simple. I'd almost recommend shutting off the ports at the switch rather than the Coraid, assuming you have good enough switches to do this reliably. On Apr 19, 2007, at 5:47 AM, Bryn M. Reeves wrote:
-- Jayson Vantuyl Systems Architect |
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