1. Ceph for Storing MeerKAT
Radio Telescope Data
Thomas Bennett
Ceph Day London 2019
2. Who are we?
International project to build the worlds largest
telescope:
• 13 countries are at the core of the SKA
• 100 organisations across about 20 countries have
been participating in the design and development of
the SKA
The South African Radio Astronomy Observatory, responsible for
managing all radio astronomy initiatives and facilities in South
Africa, including:
• MeerKAT
• African VLBI Network
• HERA
• Infrastructure and engineering planning for the SKA
“With 40% of the world’s population involved, the SKA Project is truly a global enterprise.”
https://www.skatelescope.org/participating-countries/
3. Who am I?
“Be yourself; everyone else is already taken.”
Oscar Wilde
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13. WTF?
“The most beautiful thing we can experience is the mysterious. It is the source of all true art and
science.” - Albert Einstein
14. “The most beautiful thing we can experience is the mysterious. It is the source of all true art and
science.” - Albert Einstein
WTF
16. SKAT
C3
DISK DATA
BUFFER
S3 COLD BUFFER
(policy: HDD)
SKAT
C3
FILE to S3 DATA
MOVERS
15 PB
S3 HOT BUFFER
(policy: SSD)
S3 to S3 DATA
MOVER
MKAT
C1
MKAT
C1
480 TB 2 PB
~ 900km
SARAO Data Movement
17. SARAO User Data Access
katdal.open( )
HTTPS LINK + JW TOKEN
1 – 100 million objects
S3://OBSERVATION DATA
18. SARAO Ceph Activities
• https://github.com/sratcliffe/cephmetrics
• Ceph deployment: proxmox and DIY
• Benchmarking of cluster to tune RADOS RGW parameters
• Data migration SeeKAT-C1 to SeeKAT-C3:
• Rclone sync S3 data between clusters
• Python librados implementation to sync non S3 client
pools
21. SARAO Ceph Lessons Learned
• Hardware failures
• OSD node hardware
• Using ceph balancer
• OSD sizes on SwartKAT-C1
• More lessons to be learned on SeeKAT-C1
22. OSD Node Hardware
Peralex DSS HC Storage pod
Key Features 25 GbE (SFP+)
x 48 SAS 3 connectivity
Processor Haswell-EP 4C Intel Xeon 4 core 3.7 GHz
Memory 128 GB
Networking Mellanox Network Interface Card, 25GbE, Single-Port
Drive Config 48 x 8TB HDDs
1 x 512 GB NVMe
Form Factor 4U with 1500W PSU
2.6 GB / OSD
1 CPU 3.7 GHz - 4 cores
23. Ceph Community Activities
• Locally organized Ceph
meetups
• Gitter IM community
• Ceph presentations at South
African conferences
• Document existing clusters /
users and bring them
together
25. SARAO Ceph Future Plans
• Decommission SeeKAT-C1 (70% full) and do some testing
along the way
• Upgrade to Nautilus
• Design work started for new storage cluster for MeerKAT+
(20 more dishes)
• 4 x data rate
• will require another ~20 PB raw (~15 PB ec-pools)
• Continue work to build South African Ceph community and
support current South African Ceph users