Paul von Stammwitz, Fujitsu

1. The safe way to make Ceph storage enterprise ready!
Build your own [disaster] ?
Copyright 2015 FUJITSU
Paul von Stamwitz
Sr. Storage Architect
Storage Planning, R&D Center
2015-07-16

2. 1
 The safe and convenient way to make Ceph storage enterprise ready
 ETERNUS CD10k integrated in OpenStack
 mSHEC Erasure Code from Fujitsu
 Contribution to performance enhancements

3. 2
Building Storage with Ceph looks simple
Copyright 2015 FUJITSU
Ceph
+ some servers
+ network
= storage

4. 3
Building Storage with Ceph looks simple – but……
Many new Complexities
 Rightsizing server, disk types, network
bandwidth
 Silos of management tools (HW, SW..)
 Keeping Ceph versions with versions of
server HW, OS, connectivity, drivers in sync
 Management of maintenance and support
contracts of components
 Troubleshooting
Copyright 2015 FUJITSU
Build Ceph source storage yourself

5. 4
The challenges of software defined storage
 What users want
 Open standards
 High scalability
 High reliability
 Lower costs
 No-lock in from a vendor
 What users may get
 An own developed storage system based on open
/ industry standard HW & SW components
 High scalability and reliability ? If the stack works !
 Lower investments but higher operational efforts
 Lock-in into the own stack
Copyright 2015 FUJITSU

6. 5
ETERNUS CD10000 – Making Ceph enterprise ready
Build Ceph source storage yourself Out of the box ETERNUS CD10000
incl. support
incl. maintenance
ETERNUS CD10000 combines open source storage with enterprise–class quality of service

E2E Solution Contract by Fujitsu based on Red Hat Ceph Enterprise
Easy Deployment / Management by Fujitsu
+
+
+ Lifecycle Management for Hardware & Software by Fujitsu
+

7. 6
Fujitsu Maintenance, Support and Professional Services
ETERNUS CD10000: A complete offer
Copyright 2015 FUJITSU

8. 7
Unlimited Scalability
 Cluster of storage nodes
 Capacity and performance scales by
adding storage nodes
 Three different node types enable
differentiated service levels
 Density, capacity optimized
 Performance optimized
 Optimized for small scale dev & test
 1st version of CD10000 (Q3.2014) is
released for a range of 4 to 224 nodes
 Scales up to >50 Petabyte
Copyright 2015 FUJITSU
Basic node 12 TB Performance node 35 TB Capacity node 252 TB

9. 8
Immortal System
Copyright 2015 FUJITSU
Node1 Node2 Node(n)
+
Adding nodes
with new generation
of hardware
………+
Adding nodes
 Non-disruptive add / remove / exchange of hardware (disks and nodes)
 Mix of nodes/disks of different generations, online technology refresh
 Very long lifecycle reduces migration efforts and costs

10. 9
TCO optimized
 Based on x86 industry standard architectures
 Based on open source software (Ceph)
 High-availability and self-optimizing functions are part
of the design at no extra costs
 Highly automated and fully integrated management
reduces operational efforts
 Online maintenance and technology refresh reduce
costs of downtime dramatically
 Extreme long lifecycle delivers investment protection
 End-to-end design an maintenance from Fujitsu
reduces, evaluation, integration, maintenance costs
Copyright 2015 FUJITSU
Better service levels at reduced costs – business centric storage

11. 10
One storage – seamless management
 ETERNUS CD10000 delivers one seamless
management for the complete stack
 Central Ceph software deployment
 Central storage node management
 Central network management
 Central log file management
 Central cluster management
 Central configuration, administration and
maintenance
 SNMP integration of all nodes and
network components
Copyright 2015 FUJITSU

12. 11
Seamless management (2)
Dashboard – Overview of cluster status
Server Management – Management of cluster hardware – add/remove server
(storage node), replace storage devices
Cluster Management – Management of cluster resources – cluster and pool creation
Monitoring the cluster – Monitoring overall capacity, pool utilization, status of OSD,
Monitor, and MDS processes, Placement Group status, and RBD status
Managing OpenStack Interoperation: Connection to OpenStack Server, and
placement of pools in Cinder multi-backend

13. 12
Optional use of Calamari Management GUI
12

14. 13
Example: Replacing an HDD
 Plain Ceph
 taking the failed disk offline in Ceph
 taking the failed disk offline on OS /
Controller Level
 identify (right) hard drive in server
 exchanging hard drive
 partitioning hard drive on OS level
 Make and mount file system
 bring the disk up in Ceph again
 On ETERNUS CD10000
 vsm_cli <cluster> replace-disk-out
<node> <dev>
 exchange hard drive
 vsm_cli <cluster> replace-disk-in
<node> <dev>

15. 14
Example: Adding a Node
 Plain Ceph
 Install hardware
 Install OS
 Configure OS
 Partition disks (OSDs, Journals)
 Make filesystems
 Configure network
 Configure ssh
 Configure Ceph
 Add node to cluster
 On ETERNUS CD10000
 Install hardware
• hardware will automatically PXE boot
and install the current cluster
environment including current
configuration
 Node automatically available to GUI
 Add node to cluster with mouse click
on GUI
• Automatic PG adjustment if needed

16. 15
Adding and Integrating Apps
 The ETERNUS CD10000 architecture
enables the integration of apps
 Fujitsu is working with customers and
software vendors to integrate selected
storage apps
 E.g. archiving, sync & share, data
discovery, cloud apps…
Copyright 2015 FUJITSU
Cloud
Services
Sync
& Share
Archive
iRODS
data
discovery
ETERNUSCD10000
Object Level
Access
Block Level
Access
File Level
Access
Central Management
Ceph Storage System S/W and Fujitsu
Extensions
10GbE Frontend Network
Fast Interconnect Network
PerformanceNodes
CapacityNodes

17. 16
ETERNUS CD10000 at University Mainz
 Large university in Germany
 Uses iRODS Application for library services
 iRODS is an open-source data management software in use at research
organizations and government agencies worldwide
 Organizes and manages large depots of distributed digital data
 Customer has built an interface from iRODS to Ceph
 Stores raw data of measurement instruments (e.g. research in chemistry and
physics) for 10+ years meeting compliance rules of the EU
 Need to provide extensive and rapidly growing data volumes online at
reasonable costs
 Will implement a sync & share service on top of ETERNUS CD10000

18. 17
Summary ETERNUS CD10k – Key Values
Copyright 2015 FUJITSU
ETERNUS CD10000
ETERNUS
CD10000
Unlimited
Scalability
TCO
optimized
The new
unified
Immortal
System
Zero
Downtime
ETERNUS CD10000 combines open source storage with enterprise–class quality of service

19. 18
 The safe way to make Ceph storage enterprise ready
 ETERNUS CD10k integrated in OpenStack
 mSHEC Erasure Code from Fujitsu
 Contribution to performance enhancements

20. 19
What is OpenStack
Free open source (Apache license) software governed by a non-profit foundation
(corporation) with a mission to produce the ubiquitous Open Source Cloud
Computing platform that will meet the needs of public and private clouds
regardless of size, by being simple to implement and massively scalable.
Platin
Gold
Corporate
…
…
 Massively scalable cloud operating system that
controls large pools of compute, storage, and
networking resources
 Community OSS with contributions from 1000+
developers and 180+ participating organizations
 Open web-based API Programmatic IaaS
 Plug-in architecture; allows different hypervisors,
block storage systems, network implementations,
hardware agnostic, etc.
http://www.openstack.org/foundation/companies/

21. 20
Attained fast growing customer interest
 VMware clouds dominate
 OpenStack clouds already #2
 Worldwide adoption
Source: OpenStack User Survey and Feedback Nov 3rd 2014
Source: OpenStack User Survey and Feedback May 13th 2014

22. 21
Why are Customers so interested?
Source: OpenStack User Survey and Feedback Nov 3rd 2014
Greatest industry & community support
compared to alternative open platforms:
Eucalyptus, CloudStack, OpenNebula
“Ability to Innovate” jumped from #6 to #1

23. 22
OpenStack.org User Survey Paris: Nov. 2014

24. 23
OpenStack Cloud Layers
OpenStack and ETERNUS CD10000
Physical Server (CPU, Memory, SSD, HDD) and Network
Base Operating System (CentOS)
OAM
-dhcp
-Deploy
-LCM
Hypervisor
KVM, ESXi,
Hyper-V
Compute (Nova)
Network
(Neutron) +
plugins
Dashboard (Horizon)
Billing Portal
OpenStack
Cloud APIs
RADOS
Block
(RBD)
S3
(Rados-GW)
Object (Swift)Volume (Cinder)
Authentication (Keystone)
Images (Glance)
EC2 API
Metering (Ceilometer)
Manila (File)
File
(CephFS)
Fujitsu
Open Cloud
Storage

25. 24
 The safe way to make Ceph storage enterprise ready
 ETERNUS CD10k integrated in OpenStack
 mSHEC Erasure Code from Fujitsu
 Contribution to performance enhancements

26. 25
Backgrounds (1)
 Erasure codes for content data
 Content data for ICT services is ever-growing
 Demand for higher space efficiency and durability
 Reed Solomon code (de facto erasure code) improves both
Reed Solomon Code(Old style)Triple Replication
However, Reed Solomon code is not so recovery-efficient
content data
copy copy
3x space
parity parity
1.5x space
content data

27. 26
Backgrounds (2)
 Local parity improves recovery efficiency
 Data recovery should be as efficient as possible
• in order to avoid multiple disk failures and data loss
 Reed Solomon code was improved by local parity methods
• data read from disks is reduced during recovery
Data Chunks
Parity Chunks
Reed Solomon Code
(No Local Parities) Local Parities
data read from disks
However, multiple disk failures is out of consideration
A Local Parity Method

28. 27
 Local parity method for multiple disk failures
 Existing methods is optimized for single disk failure
• e.g. Microsoft MS-LRC, Facebook Xorbas
 However, Its recovery overhead is large in case of multiple disk failures
• because they have a chance to use global parities for recovery
Our Goal
A Local Parity Method
Our goal is a method efficiently handling multiple disk failures
Multiple Disk Failures

29. 28
 SHEC (= Shingled Erasure Code)
 An erasure code only with local parity groups
• to improve recovery efficiency in case of multiple disk failures
 The calculation ranges of local parities are shifted and partly overlap with each
other (like the shingles on a roof)
• to keep enough durability
Our Proposal Method (SHEC)
k : data chunks (=10)
m :
parity
chunks
(=6)
l : calculation range (=5)

30. 29
1. mSHEC is more adjustable than Reed Solomon code,
because SHEC provides many recovery-efficient layouts
including Reed Solomon codes
2. mSHEC’s recovery time was ~20% faster than Reed
Solomon code in case of double disk failures
3. mSHEC erasure-code included in Hammer release
4. For more information see
https://wiki.ceph.com/Planning/Blueprints/Hammer/Shingled_Erasure_Code_(SHEC)
or ask Fujitsu
Summary mSHEC

31. 30
 The safe way to make Ceph storage enterprise ready
 ETERNUS CD10k integrated in OpenStack
 mSHEC Erasure Code from Fujitsu
 Contribution to performance enhancements

32. 31
Areas to improve Ceph performance
Ceph has an adequate performance today,
But there are performance issues which prevent us from taking full
advantage of our hardware resources.
Two main goals for improvement:
(1) Decrease latency in the Ceph code path
(2) Enhance large cluster scalability with many nodes / ODS

33. 32
LTTng general http://lttng..org/
General
 open source tracing framework for Linux
 trace Linux kernel and user space applications
 low overhead and therefore usable on
production systems
 activate tracing at runtime
 Ceph code contains LTTng trace points already
Our LTTng based profiling
 activate within a function, collect timestamp information at the interesting places
 save collected information in a single trace point at the end of the function
 transaction profiling instead of function profiling: use Ceph transaction id's to
correlate trace points
 focused on primary and secondary write operations

34. 33
Turn Around Time of a single Write IO

35. 34
LTTng data evaluation: Replication Write
Observation:
 replication write latency suffers from the "large variance problem"
 minimum and average differ by a factor of 2
 This is a common problem visible for many ceph-osd components.
Why is variance so large?
 Observation: No single hotspot visible.
 Observation: Active processing steps do not differ between minimum and average
sample as much as the total latency does.
Additional latency penalty mostly at the switch from
 sub_op_modify_commit to Pipe::writer
 no indication that queue length is the cause
Question: Can the overall thread load on the system and Linux scheduling be the
reason for the delayed start of the Pipe::writer thread?

36. 35
Thread classes and ceph-osd CPU usage
Thread per ceph-osd depends on complexity of Ceph cluster: 3x node with 4 OSDs
each ~700 threads per node; 9x nodes with 40 OSDs each > 100k threads per node
 ThreadPool::WorkThread is a hot spot = work in the ObjectStore / FileStore
total CPU usage during test 43.17 CPU seconds
Pipe::Writer 4.59 10.63%
Pipe::Reader 5.81 13.45%
ShardedThreadPool::WorkThreadSharded 8.08 18.70%
ThreadPool::WorkThread 15.56 36.04%
FileJournal::Writer 2.41 5.57%
FileJournal::WriteFinisher 1.01 2.33%
Finisher::finisher_thread_entry 2.86 6.63%

37. 36
FileStore benchmarking
 most of the work is done in FileStore::do_transactions
 each write transaction consists of
 3 calls to omap_setkeys,
 the actual call to write to the file system
 2 calls to setattr
 Proposal: coalesce calls to omap_setkeys
 1 function call instead of 3 calls, set 5 key value pairs instead of 6 (duplicate key)
 Official change was to coalesce at the higher PG layer

38. 37
Other areas of investigation and improvement
 Lock analysis
 RWLock instead of mutex
 Start with CRC locks
 Bufferlist tuning
 Optimize for jumbo packets
 malloc issues
Copyright 2015 FUJITSU

39. 38
Summary and Conclusion
ETERNUS CD10k is the safe way to make Ceph enterprise ready
 Unlimited Scalability: 4 to 224 nodes, scales up to >50 Petabyte
 Immortal System with Zero downtime: Non-disruptive add / remove /
exchange of hardware (disks and nodes) or Software update
 TCO optimized: Highly automated and fully integrated management reduces
operational efforts
 Tight integration in OpenStack with own GUI
Fujitsu will continue to enhance ease-of-use and performance
 This is important!
 As Ceph’s popularity increases, competitors will attack Ceph in these areas.

40. 3939 Copyright 2015 FUJITSU
pvonstamwitz@us.fujitsu.com