<FONT face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size=2><br><div><br>&gt;<br>&gt;An&nbsp;OST&nbsp;can&nbsp;be&nbsp;an&nbsp;externally&nbsp;connected&nbsp;(logical)&nbsp;disk&nbsp;such&nbsp;as&nbsp;a&nbsp;DDN<br>&gt;LUN<br>&gt;connected&nbsp;by&nbsp;fibre&nbsp;channel&nbsp;to&nbsp;the&nbsp;OSS.&nbsp;&nbsp;An&nbsp;OST&nbsp;can&nbsp;also&nbsp;be&nbsp;connected<br>&gt;internally&nbsp;in&nbsp;the&nbsp;OSS&nbsp;such&nbsp;as&nbsp;a&nbsp;SATA,&nbsp;SCSI,&nbsp;(or&nbsp;heaven&nbsp;forbid)&nbsp;and<br>&gt;IDE<br>&gt;disk.<br>&gt;<br>&gt;Am&nbsp;I&nbsp;to&nbsp;understand&nbsp;you&nbsp;want&nbsp;the&nbsp;latter?&nbsp;&nbsp;Do&nbsp;you&nbsp;already&nbsp;have&nbsp;this<br>&gt;hardware&nbsp;configuration&nbsp;and&nbsp;you&nbsp;just&nbsp;want&nbsp;to&nbsp;(re-)deploy&nbsp;it&nbsp;with<br>&gt;Lustre?<br>&gt;<br><br>Indeed. We'd like to construct a mass capacity matrix, and are<br>currently weighing risk and recovery into the equation.<br><br>&gt;The&nbsp;reason&nbsp;being,&nbsp;is&nbsp;that&nbsp;Lustre&nbsp;can&nbsp;only&nbsp;achieve&nbsp;it's&nbsp;HA<br>&gt;deliver-ability&nbsp;goals&nbsp;when&nbsp;two&nbsp;OSSes&nbsp;(or&nbsp;MDSes)&nbsp;can&nbsp;see&nbsp;a&nbsp;common<br>&gt;storage<br>&gt;target.&nbsp;&nbsp;Doing&nbsp;this&nbsp;with&nbsp;internally&nbsp;connected&nbsp;disks&nbsp;is&nbsp;difficult&nbsp;and<br>&gt;usually&nbsp;requires&nbsp;a&nbsp;replication&nbsp;technology&nbsp;like&nbsp;DRBD&nbsp;to&nbsp;ensure&nbsp;that<br>&gt;the<br>&gt;(i.e.&nbsp;network&nbsp;mirrored)&nbsp;disks&nbsp;are&nbsp;in&nbsp;sync.&nbsp;&nbsp;This&nbsp;is&nbsp;a&nbsp;Sun-unsupported<br>&gt;configuration,&nbsp;but&nbsp;there&nbsp;have&nbsp;been&nbsp;reports&nbsp;of&nbsp;success&nbsp;on&nbsp;this&nbsp;list.<br>&gt;<br>&gt;&gt;&nbsp;This&nbsp;being&nbsp;said,&nbsp;can&nbsp;someone&nbsp;pinpoint&nbsp;me&nbsp;to&nbsp;a&nbsp;possibly&nbsp;high&nbsp;level<br>&gt;&gt;&nbsp;diagram&nbsp;of&nbsp;how&nbsp;redundancy&nbsp;can&nbsp;be&nbsp;implemented&nbsp;across&nbsp;nodes,&nbsp;if<br>&gt;&gt;&nbsp;possible?<br>&gt;<br>&gt;I&nbsp;don't&nbsp;know&nbsp;of&nbsp;any&nbsp;diagrams,&nbsp;but&nbsp;typically,&nbsp;you&nbsp;connect&nbsp;redundant<br>&gt;OSSes<br>&gt;to&nbsp;dual-ported&nbsp;disks&nbsp;so&nbsp;that&nbsp;either&nbsp;OSS&nbsp;can&nbsp;serve&nbsp;it's&nbsp;data.&nbsp;&nbsp;When<br>&gt;one<br>&gt;dies,&nbsp;the&nbsp;other&nbsp;takes&nbsp;over.<br><br>I see. I was under the impression that mirroring was part of the Lustre package <br>already. Am I correct to say that Lustre does handle the concatenation <br>of OST volumes? <br><br>Perhaps someone with DRBD experience can expand on that, as that would<br>be quite helpful. Is Lustre aware of DRBD? vice-versa?<br><br>Thanks for the Information Brian. It's very helpful.<br><br><br>&gt;<br>&gt;b.<br><br></div></FONT>