Memcached crashing on older Xeon CPU

enko · September 6, 2021, 7:24pm

I’ve ran into an issue trying to run couchbase (7.0.0) in production. This is an older server - with e5 2670 v3 CPU.

Memcached is not starting and logs this message:

Service 'memcached' exited with status 1. Restarting. Messages:
2021-09-06T19:05:11.445509+00:00 CRITICAL Failed to initialise - CPU with SSE4.2 extensions is required - terminating.

2670 v3 only supports: AVX2

It appears to be triggered by this:

github.com

couchbase/kv_engine/blob/master/daemon/memcached.cc#L863

    
      
          
          
#if CB_DEVELOPMENT_ASSERTS
              LOG_INFO_RAW("Development asserts enabled");
          #endif
          
          
#if defined(__x86_64__) || defined(_M_X64)
              if (!folly::CpuId().sse42()) {
                  // MB-44941: hw crc32 is required, and is part of SSE4.2. If the CPU
                  // does not support it, memcached would later crash with invalid
                  // instruction exceptions.
                  FATAL_ERROR(EXIT_FAILURE,
                              "Failed to initialise - CPU with SSE4.2 extensions is "
                              "required - terminating.");
              }
          #endif
          
          
    try {
                  cb::backtrace::initialize();
              } catch (const std::exception& e) {
                  LOG_WARNING("Failed to initialize backtrace support: {}", e.what());
              }

Is there any way of running couchbase on this machine?
Thank you.

edit:
Just tried 6.6.3 - no such issue. Hope its just a bug.

enko · September 7, 2021, 12:02am

Looks like support was dropped for older CPUs
https://docs.couchbase.com/server/current/install/pre-install.html

**Minimum Specifications**

CPU
	

2 GHz dual core x86_64 CPU supporting SSE4.2
	

3 GHz quad core x86_64 CPU supporting SSE4.2 and above

3 GHz six core x86_64 CPU supporting SSE4.2 when using Cross Datacenter Replication (XDCR) and Views

drigby · September 7, 2021, 2:50pm

Note that SSE4.2 pre-dates AVX2 - it’s been present on all Intel CPUs since Nehalem in 2008. Your CPU is Haswell micro-architecture (see Intel Xeon Processor E52670 v3 30M Cache 2.30 GHz Product Specifications) and does have SSE4.2 support.

If the CPU is not reporting SSE4.2 as available, that suggests it is disabled somewhere - possibly in the BIOS, or if this is a VM then perhaps the Hypervisor doesn’t support it / doesn’t have it enabled.

enko · September 7, 2021, 4:09pm

Thank you, VM was mis-configured. Its running in proxmox - and had to be set to ‘host’ in hardware/CPU field.