<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">In principal this is true.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>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).</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>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.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>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).</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>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.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>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.</DIV><DIV><BR><DIV><DIV>On Apr 19, 2007, at 5:47 AM, Bryn M. Reeves wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">-----BEGIN PGP SIGNED MESSAGE-----</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Hash: SHA1</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Kadlecsik Jozsi wrote:</DIV> <BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">On Thu, 19 Apr 2007, Jayson Vantuyl wrote:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> <BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">It is supposedly possible to script using the mask command to block servers on</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">individual MAC address to the AoE storage.<SPAN class="Apple-converted-space"> </SPAN>While this is often offered by</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Coraid support as an option, I've not seen anyone implement it.<SPAN class="Apple-converted-space"> </SPAN>To be sure, I</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">have my doubts about it anyways, give that the utility that you automate (cec)</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">does not exactly provide an API (you actually are writing directly into the</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">unit's console!).</DIV> </BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I have already written the script which does exactly that: i.e it calls<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">'cec' and issues the proper mask command to disable/enable access to the<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">logical blades. Now I only have to test it in our first testbed GFS setup<SPAN class="Apple-converted-space"> </SPAN></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">;-).</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> </BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">This doesn't seem so unreasonable - the fence_apc script does a similar</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">thing, connecting to the console over telnet and squirting commands into</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">the device's menu system.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Kind regards,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Bryn.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">-----BEGIN PGP SIGNATURE-----</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Version: GnuPG v1.4.7 (GNU/Linux)</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Comment: Using GnuPG with Fedora - <A href="http://enigmail.mozdev.org">http://enigmail.mozdev.org</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">iD8DBQFGJ0jI6YSQoMYUY94RAkswAJ9k4Yym/PHs/Bwj9AXz0dXTgPCoJACgnoLQ</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">MEJ63uWPdBTdGMo+GYuJtyo=</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">=HL8a</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">-----END PGP SIGNATURE-----</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">--</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Linux-cluster mailing list</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="mailto:Linux-cluster@redhat.com">Linux-cluster@redhat.com</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="https://www.redhat.com/mailman/listinfo/linux-cluster">https://www.redhat.com/mailman/listinfo/linux-cluster</A></DIV> </BLOCKQUOTE></DIV><BR></DIV><BR><BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>-- </DIV><DIV>Jayson Vantuyl</DIV><DIV><FONT class="Apple-style-span" size="2"><SPAN class="Apple-style-span" style="font-size: 10px;"><SPAN class="Apple-style-span" style="font-size: 10px; "><SPAN class="Apple-style-span" style="font-size: 10px; ">Systems Architect</SPAN></SPAN></SPAN></FONT></DIV><DIV><B style="font-weight: bold; "><A href="http://www.engineyard.com"><SPAN class="Apple-style-span" style="font-weight: normal;; color: rgb(0, 0, 238); -khtml-text-decorations-in-effect: underline; "><SPAN class="Apple-style-span" style="color: rgb(0, 0, 238); -khtml-text-decorations-in-effect: underline; ">Engine Yard</SPAN></SPAN></A></B></DIV><DIV><FONT class="Apple-style-span" size="2"><SPAN class="Apple-style-span" style="font-size: 10px;"><SPAN class="Apple-style-span" style="font-size: 10px; "><SPAN class="Apple-style-span" style="font-size: 10px; "><A href="mailto:jvantuyl@engineyard.com">jvantuyl@engineyard.com</A></SPAN></SPAN></SPAN></FONT></DIV></SPAN><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></BODY></HTML>