With the fee of recent RAM soaring, Meta has found a thrifty method to reuse older memory in newer servers.
The performance of about 40% of Meta’s thousands and thousands of servers is proscribed by an absence of memory, the corporate said — however it has a surplus of older DIMMs from decommissioned servers, because RAM chips can last about twice so long as the remaining of the machine.
To cash in on this imbalance, it developed a custom Computer Express Link (CXL) chip it calls Vistara, and associated software, to decouple older memory from server memory channels, enabling its reuse in recent machines alongside their native memory. Using the older RAM with the CXL interface doesn’t significantly affect performance — although it will have done if the older DIMMs were plugged straight into newer servers.