Lenovo Support in Mexico After End of Life

Capacity That Was Never Missing

A ThinkSystem or System x machine reports substantially less memory than is physically fitted. The natural conclusion is a failed module, and a diagnostic exercise begins. On a meaningful number of estates the answer is that nothing has failed and the machine has been reporting exactly this figure since the day it was commissioned.

Mirroring Halves Usable Capacity by Design

Memory mirroring writes every value to two modules so that an uncorrectable error in one can be survived. It is a deliberate trade of capacity for resilience, entirely appropriate for some workloads, and it halves what the operating system sees. Rank sparing does something similar for similar reasons, reserving capacity rather than duplicating it.

It Was Set Once and Never Revisited

These modes are configured during a build, frequently by an integrator following a template, and there is no subsequent event that prompts anyone to re-examine the decision. Years later the people running the machine have no reason to suspect a mode is in force, because everything about the estate is consistent with the number the system reports.

It Changes What an Upgrade Delivers

This is why it matters commercially rather than merely as a curiosity. Under mirroring, adding modules delivers half their nominal capacity, so an upgrade sized against the observed shortfall falls short by the same amount again. ICD checks the operating mode before quoting memory, across ThinkSystem and System x generations past vendor support, tested and covered for one to three years.