Red Hat Ceph Storage Acceleration Utilizing Flash Technology

RED HAT CEPH STORAGE ACCELERATION UTILIZING FLASH TECHNOLOGYApplications and Ecosystem Solutions Development

Rick Stehno

Red Hat Storage Day - Boston 2016 1

Seagate Confidential 2

• Utilize flash caching features to accelerate critical data. Caching methods can be write-back for writes, write-thru for disk/cache transparency, read cache, etc..

• Utilize storage tiering capabilities. Performance critical data resides on flash storage, colder data resides on HDD

• Utilize all flash storage to accelerate performance when all application data is performance critical or when the application does not provide the features or capabilities to cache or to migrate the data

Three ways to accelerate application performance with flashFlash Acceleration for Applications


Configurations:• All flash storage - Performance

• Highest performance per node

• Less maximum capacity per node

• Hybrid HDD and flash storage - Balanced• Balances performance, capacity and cost

• Application and workload suitable for

• Performance critical data on flash

• Utilize host software caching or tiering on flash

• All HDD storage - Capacity• Maximum capacity per node, lowest cost

• Lower performance per node

Ceph Software Defined Storage (SDS) Acceleration


–Higher performance in half the rack space

–28% less power and cooling

–Lower MTBF inherent with reduced component count

–Reduced OSD recovery time per Ceph node

–Lower TCO

Why 1U server with 10 NVMe SSDs may be better choice vs. 2U Server with 24 SATA SSDs

Storage - NVMe vs SATA SSD


• 4.5x increase for 128k sequential reads

• 3.5x increase for 128k sequential writes

• 3.7x increase for 4k random reads

• 1.4x increase for 4k random 70/30 RR/RW

• Equal performance for 4k random writes


All Flash Storage - NVMe vs SATA SSD cont’d

FIO Benchmarks



All Flash Storage - NVMe vs SATA SSD cont’d

Increasing the load to stress NVMe capabilities over and above the 128 thread SATA SSD Test:

• 5.8x increase for Random Writes at 512 threads

• 3.1x increase for 70/30 RR/RW at 512 threads

• 4.2x increase for Random Reads at 790 threads

• 8.2x increase for Sequential Reads at 1264 threads

3x

5.8x

1.4x

3.1x

1.0x

4.2x

1.3x

8.2x

Ceph RBD NVMe Performance Gains over SATA SSD

Random Write 70/30 RR/RW Random Reads Sequential Reads

Gai

ns

Random Writes 70/30 RR/RW Random Reads Sequential Reads

128k FIO RBD IOEngine Benchmark


Price per MB/s: Cost of ((Retail Cost of SSD) / MB/s for each test)

SSDTotal SSD

Price Price MB/s 128k Random Writes

128 threadsPrice MB/s 128k Random Writes

512 threads

24 - SATA SSD 960G $7,896 24 - SATA SSD 960G $15.00

10 - NVMe 2TB $10,990 10 - NVMe 2TB $7.00 10 – NVMe 2TB $3.00

These prices do not include savings from electrical/cooling costs, reducing datacenter floor space, from the reduction of SATA SSD

Note: 128k random write FIO RBD benchmark: SATA SSD averaged 85% busy, NVMe averaged 80% busy with 512 threads

FIO RBD Maximum Threads Random Write Performance for NVMe

Ceph Storage Costs Seagate SATA SSD vs. Seagate NVMe SSD


MySQL• MySQL is the most popular and the most widely used open-source database in the world

• MySQL is both feature rich in the areas of performance, scalability and reliability

• Database users demand high OLTP performance - Small random reads/writes

Ceph• Most popular Software Defined Storage system

• Scalable

• Reliable

Does it make sense implementing Ceph into a MySQL Database environment?

But Ceph was not designed to provide high performance for OLTP environments OLTP entails small random reads/writes


MySQL Setup:

Release 5.745,000,000 rows6GB Buffer4G logfilesRAID 0 over 18 HDD

Ceph Setup:

3 Nodes each containing:Jewel Using Filestore4 NVMe SSDs1 Pool over 12 NVMe SSDsReplica 240G private and public network

For all tests, all MySQLfiles were local on local server except the database file, this file was moved to the Ceph cluster.

MySQL - Comparing Local HDD to Ceph Cluster

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MySQL - Comparing Local HDD to Ceph ClusterMySQL - Comparing Local HDD to Ceph Cluster


MySQL - Comparing Local NVMe SSD to Ceph Cluster MySQL Setup:

Release 5.745,000,000 rows6GB Buffer4G logfilesRAID 0 over 4 NVMe SSDs

Ceph Setup:

3 Nodes each containing:Jewel Using Filestore4 NVMe SSDs1 Pool over 12 NVMe SSDsReplica 140G private and public network

For all tests, all MySQLfiles were local on local server except the database file, this file was moved to the Ceph cluster.


All SSD

Case-1: Case-2:Case-3:2 SSDs 2 SSDs

1 PCIe flash1 OSD/SSD 4 OSDs/SSD

4 OSDs/SSD

8 OSD journals on PCIe flash

2 ssd, 2 osd 2 ssd, 8 osd 2 ssd, 8 osd, +journal

0

200000

400000

600000

800000

1000000

1200000

0

100000

200000

300000

400000

500000

600000

700000

800000

FIO Random Write - 200 Threads - 128k Data

KB/s

IOPS

Seagate SSD and Seagate PCIe Storage using AIC serverCeph All Flash Storage Acceleration


• Use RAW device or create 1st partition on 1M boundary (sector 2048)• Ceph-deploy uses the optimal alignment when creating an OSD

• Use blk-mq/scsi-mq if kernel supports it

• rq_affinity = 1 for NVMe, rq_affinity = 2 for non-NVMe

• rotational = 0

• blockdev --setra 4096

Linux tuning is still a requirement to get optimum performance out of a SSDLinux Flash Storage Tuning


• If using an older kernel that doesn’t support BLK-MQ, use:• “deadline” IO-Scheduler with supporting variables:

• fifo-batch• front-merges• writes-starved

• XFS Mount options:• nobarrier,discard,noatime,attr2,delaylog,inode64,noquota

• If using a smaller number of SSD/NVMe SSD, test with creating multiple OSD’s per SSD/NVMe SSD. Have seen good performance increases using 4 OSD per SSD/NVMe SSD

• MySQL – when using flash, configure both innodb_io_capacity and innodb_lru_scan_depth

Linux tuning is still a requirement to get optimum performance out of a SSD

Linux Flash Storage Tuning cont’d


Flash Storage Device ConfigurationIf the NVMe SSD or SAS/SATA SSD device can be configured to use a 4k sector size, this could increase performance for certain applications like databases.

For all of my FIO tests with the RBD engine and for all of my MySQL tests, I saw up to a 2x improvement (depending on the test) when using 4k sector sizes compared to using 512 byte sectors.

Storage devices used for all of the above benchmarks/tests:

• Seagate Nytro XF1440 NVMe SSD • Seagate Nytro XF1230 SATA SSD• Seagate 1200.2 SAS SSD • Seagate XP6500 PCIe Flash Accelerator Card


Seagate Broadest PCIe, SAS and SATA Portfolio

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Thank You! Questions?

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