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The source of the Lustre stability problem has been narrowed to a specific software+hardware configuration on farm node clients (Alma 9.3 + Connect-X 3) that can destabilize servers and eventually affect all sytems with Lustre access. We are vetting potential
fixes now. During this process, subsets of farm nodes will be taken offline to apply and test changes.</div>
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For the interested, a longer update on troubleshooting follows:</div>
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In the farm there are generations of Mellanox InfiniBand adapters including Connect-X 3, 4, 5, and 6. During a period of troubleshooting last week, we were able to tie the cause of the Lustre instability to Alma 9 Linux Clients with Connect-X 3 cards. When
these clients suddenly become unstable after some period of smooth operation, they eventually trigger kernel-level problems on Lustre servers than then affect all lustre clients. </div>
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We were further able to demonstrate this behavior with multiple Lustre filesystems and server versions, helping to rule out a specific server as the cause. The Connect-X 3 client driver is different and older than the driver for the newer cards. In two subsets
of farm19 nodes, only those with the Connect-X 3 cards caused instability in the servers; the farm19 nodes with Connect-X 4 did not. </div>
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We are pursuing two paths. First, we are testing if kernel and driver updates in the Alma or upstream provide a fix. Second, we are looking at the possibility of replacing a larger set of Connect-X 3 cards with Connect-X 4, stepping off the older driver code. </div>
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Thank you for your understanding as we work toward a stable set of hardware and software configurations that accommodate all generations of the farm nodes. </div>
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