1 Paolo Bianco Storage Architect Sun Microsystems An overview on Hybrid Storage Technologies

2... instead of buying several dozens of high speed low capacity drives Agenda The Storage Evolution Anatomy of an SSD Why Solid State Drives? Sun SSD Strategy and Portfolio ZFS and the Hybrid Storage Pool An overview on Hybrid Storage Technologies

3 Disk to CPU Discontinuity Today’s CPU have become I/O starved CPU Performance Improvement in 6Y = 10x HDD Performance improvement in 6Y = 1,5x As a result, storage systems are hopelessly unbalanced between controller capability and storage pool performance

4 Why IOPS matter (usually more than transfer rate) For many accesses, the non-transfer time component is dominant. IOPS is one metric reflecting this component.

5 Storage Evolution Time for a change?

6 New Server Memory Hierarchy

7 SSDs Keep Up w/ CPU Moore’s Law controls both

8 Anatomy of an SSD

9 NAND Basics Single Level Cell (SLC) > 30MB/sec per Die (Write) > Data Retention: 10 years > Endurance: 100,000 cycles > x price of MLC > 45 nm SLC has ~ 500 electrons in the floating gate > Focus on reliability and performance Multi Level Cell (MLC) > 10MB/sec per Die (Write) > Data Retention: 3-4 years > Endurance: 1,500 cycles > 2.0 x capacity of SLC > 45 nm MLC has ~ 100 electrons from level to level > Focus on capacity

10 From Flash memory to SSD

11 Typical SSD Block diagram

12 Typical SSD: What's in the box?? Flash Memory Controller DRAM Host Interface Flash Gang Power Capacitor ARM Processor

13 Why Solid State Drives?

14 Why SSD?: Performance

15 How many 15krpm drives = 1 SSD? Random 8k writes

16 How many 15krpm drives = 1 SSD? Random 8k reads

17 Why SSD?: Energy

18 SSD Power Efficiency Most HDDs and SSDs specify “Active” power > No standard definition of what “active” means > Analogous to “litres per hour at maximum speed” > Only useful comparison if everyone has same maximum speed What matters is IOPS/Watt (Enterprise) or power curve (Client) > For enterprise applications measure work done per Watt consumed under a specific workload – Analogous to “Km per liter (city)” > For client applications measure power for representative usage with standard benchmarks (ie MobileMark, etc) – Analogous to “litres per standardized 200-kms road trip”

19 Enterprise SSD > 7,000 Write IOPS > 35,000 Read IOPS > 32GB > ~3W $ per IOPS: 0.04 IOPS/W: ~7000 Enterprise HDD > 180 Write IOPS > 320 Read IOPS > 300 GB > ~18W $ per IOPS: 2.43 IOPS/W: ~14 Cost Effective Performance SSDs are 70X more cost effective

20 Why SSD?: Reliability

21 SSD Reliability has two parts MTBF > Measure of time between failures due to manufacturing or component defects > 1.5~2 million hours typical for an enterprise SSD Endurance > All SSDs wear out due to data writes > Indication of life based on an usage condition > Usage conditions vary for consumer and performance products > Enterprise SSDs are specified to last several years under predefined usage conditions

22 Endurance Factors Wear-leveling efficiency Write amplification NAND cycles SSD densities

23 What's Wear Leveling ? Wear-leveling: a set of algorithms that attempt to maximize the lifetime of flash memory by evening out the use of individual cells.

24 Sun SSD Strategy and Portfolio

25 Prediction 1: SSD will be more cost effective in 2009 SSD predictions

26 Prediction 2: SSD will be bigger in capacity in 2015 SSD predictions

27 Where to Store Data? Optimization Trade-Off

28 Where to deploy SSDs? Storage or Server?

29 Sun SSD Strategy Step 1 – HDD Replacement

30 Sun SSD Strategy Step 2 – Lightning Flash Array

31 ZFS and the Hybrid Storage Pool

32 ZFS Hybrid Storage Pools SSDs Accelerate Synchronous Writes ZFS caches blocks in system main memory (DRAM) This cache is called the ZFS Adaptive Replacement Cache (ARC) All synchronous writes go to the ZFS Intent Log (ZIL) before they can complete > Database logs, NFS servers ZFS can separate the ZIL onto separate devices (ZFS log devices or slogs) Putting the ZIL on SSDs will greatly accelerate the performance of synchronous writes DRAM SSD HDD

33 ZFS Hybrid Storage Pools SSDs Accelerate Reads – ARC & L2ARC Older/least frequently accessed blocks in the ARC have to be evicted for newer data blocks or due to application demands for memory Blocks evicted from the ARC are written into L2ARC On reads, if we miss the ARC we go to the L2ARC If the reads miss the L2ARC we go to disk DRAM SSD HDD

34 ZFS Hybrid Storage Pools Faster, Cheaper, Less Power Enterprise HDDs Hybrid Storage Pool High Capacity HDDs SSDs More IOPS Lower $GB Lower Power Consumption Less Rack Space

© 2009 Sun Microsystems, Inc. CONFIDENTIAL – NDA REQUIRED Thank You! An overview on Hybrid Storage Technologies 35 Paolo Bianco Storage Architect Sun Microsystems