Beating the virtualization tax for NoSQL workloads with OSv

Don Marti and Glauber CostaCloudius Systems

Hardware

Hypervisor

guest OS

JVM

App Server

Java App

What is OSv?

guest OS

C++ App

Hardware

Hypervisor

OSv VM

App Server

Your App

OSv VM

Your App

Before After

Performance and Manageability

■ Performance■ Single address space■ Simplified networking

■ Manageability■ No local users■ No local config files

■ Simplicity: less than 1 second boot time

Trust is not free

Colocated (same CPU)

Apart(different CPU)

Linux 905 ns 13148 ns

OSv 328 ns 1402 ns

■ Context switch microbenchmark

No config files

■ REST API for all configurable items

■ AJAX GUI for config and management (optional)

VM build and deploy

■ Capstan: rapid VM build (and run)■ Docker-like config file■ Takes about 3 seconds to build■ Runs on any OS (written in Go)

1. Network performance

Traditional stack Network Channels

OSv-specific networking

■ Bypass socket layer■ full zero-copy achievable

Memcached benchmark

Requests/s (higher is better)

OSv networking: inbound

■ Handle inbound data without the overhead of the socket layer.

■ Called for every incoming packet.

OSv networking: outbound

■ Send the frame directly to the ifnet device.

■ PF hook is called with relevant locks held.

2. Memory management

Manual memory tuning

■ 240,000 Google hits for [jvm heap size]■ This is a job for a computer, not a human being.

JVM Memory System memory

Lend memory

Memory ballooning

Shrinker API

■ Register a callback■ OSv calls your shrinker■ No manual tuning of cache size

■ Used in osv-memcached

Redis on OSv

“porting” Redis

make CFLAGS="-fPIC" LDFLAGS="-shared" MALLOC=libc

■ -fPIC option■ -shared option■ MALLOC=libc (not required)

■ OSv malloc is integrated with kernel, optimized for small objects.

Details on Redis test

■ Ubuntu 14.04■ Affinity turned on in the Ubuntu guest

■ Both systems: Amazon c3.8xlarge■ 32 vCPUs■ 60GB RAM■ Intel Xeon E5-2680 v2 @ 2.8GHz■ 10 Gigabit networking

Redis details

■ Lua scripting, PUB/SUB, etc, it all works■ Redis uses fork for “BGSAVE” command.

■ This is the only functionality not supported.■ Single address space, no copy on write.■ Less than 20Mb redis image, now bootable

everywhere.

Conclusions

■ Memory and CPU intensive loads can have unacceptable performance under virtualization.

■ The OSv project has profiled important bottlenecks for NoSQL applications.

■ Virtual appliances available: Cassandra, Tomcat, Redis

■ Work in progress. Please join us.

Thank you

Download or try it in the cloud at: http://osv.io/

Follow @CloudiusSystems on Twitter

Begin backup slides

Run most workloads on any cloud

OSv

Rapid VM build and deploy

■ Build an OSv VM in ~3 seconds■ Small VMs (as small as 10MB) for fast deploy■ Boot in ~1 second for resilience and scaling■ Enable continuous delivery

Performance

■ System calls are free■ context switches are cheap (4x speed of recent Linux)

■ Network performance significantly faster■ around 20% with netperf over recent Linux■ more than 50% for some UDP workloads

■ SpecJVM between 3 and 5% faster■ Boots in < 1 second

■ As little as 100-200ms without local filesystem

Virtualization Oriented

■ No spinlocks in the kernel■ Simplest solution to lock holder preemption

■ No complicated hardware model■ Fair scheduler■ Huge pages■ Single address space: one set of page tables

So what about containers?

■ Docker is awesome! Low overhead!■ Small artifacts■ Fast deployment■ Fast startup (container start, not OS boot)

■ Docker is awesome! Easy builds!■ Simple configuration file■ Minimal additional work on top of application build

Docker is awesome

Hypervisors are awesome, too

■ Live migration (load balance, hardware maint)■ Multiple kernel versions available■ Running VMs everywhere is awesome!

■ Public cloud, private cloud, existing hypervisor...■ Security is awesome!

■ Container attack surface is full kernel interface.■ Hypervisor attack surface is small.

■ Fast boot, fast provisioning■ High performance■ Tiny footprint■ Virtualized

■ Live migration■ Elasticity■ MMU access

Everything is awesome

Different customization levels

● JVM-based application○ No effort

● Traditional C/C++ application○ More effort

● Virtio-app○ NFV - highest gain

C++ simplifies flow of control

Run existing applications

■ Open source, POSIX-compatible■ Run native Linux applications■ Run Java applications

Network channels: before

Network channels: after