Leonardo
EuroHPC-CINECA · DDN Exascaler · Fully Reproducible
System Purpose
Question asked
Please describe the purpose and general usage of the submitted system. This would include the types of typical applications it supports (e.g., defense applications, molecular dynamics, benchmarking, system test, systems research), and the general use and purpose of the data generated by the applications running on it.
This system aims at supporting public and private European research. As such, it hosts a bunch of different users from any country in the EU and a wide variety of applications (CFD, genetic research, astrophysics, climate simulation, you name it ...)
Availability
Question asked
Please provide the deployment timeframe of the submitted system, or for on-demand cloud systems, the general period over which it is deployed and destroyed.
Please describe the availability of the system to users and who are its set of most regular users.
This system was deployed end of 2022 and will be available for 5 to 6 years.
The users are researchers and laboratories in the EU from many scientific areas.
Storage System Software
Question asked
How is this storage software available? (e.g., commercially, open-source, not publicly available) Note that if the storage software is not open-source or commercially available, then a general description would be requested, but this would limit the submission’s reproducibility score.
Can anyone download/purchase this software?
List either product webpage or open-source repo of the exact software used in IO500.
Give any and all additional details of this specific storage deployment: (e.g., type of storage server product such IBM ESS or DDN SFA400X2, use of Ext4 or some other file system on each storage node, dual connected storage media to storage servers).
The purpose of this system is scientific and academic research.
Given the number and variety of applications, I can't make a list here. Some are open-source, some are commercial.
The storage used for this deployment relies on DDN's EXAscaler offer:
- The latest ES400NVX2 for the flash-based storage
- The ES7990X for the hard-drives based storage
- The ES400NVX (1st gen) for the metadata storage (flash)
The software used is EXA6, based on Lustre 2.14. The backend filesystem used is ldiskfs.
Data is transferred over an Infiniband HDR200 network down to clients connected as HDR100.
Runtime Environment
Question asked
State here that you provided all scripts/documentation that would allow someone else to reproduce your environment and attempt to achieve a similar IO500 score as the submitted system.
NOTE: provide all files/documentation/scripts that would enable a user to build your environment and deploy the custom scripts, software, or config files once they have obtained the appropriate storage system hardware and software. These may be included into the io500.tgz or into the extraCodes upload on the submission form.
Several examples include:
- Commands used to set striping information (either for the entire system or for particular directories)
- File system config and tuning information (or a reason why this is not available due to lack of root access, etc) on each node type (e.g., non-default config parameters on all three types of Lustre nodes: MDS, OSS, and client)
- Any additional scripts utilized that impact IO500 execution beyond the io500 config file. For example, with IBM Spectrum Scale, the output of mmlsconfig, mmlscluster, mmlsfs, and mmlsfileset commands (and possibly even a dump of the configuration if possible). Each file system probably has similar type of config/tuning information that would need to be shared for a user to fully reproduce the environment.
All of the scripts to submit the same io500 are enclosed in the submitted tarball.
The filesystem was setup with the following tunings:
osc.lscratch*.max_pages_per_rpc: 16M
osc.lscratch*.max_rpcs_in_flight: 8
llite.lscratch*.max_read_ahead_mb: 2048
osc.lscratch*.max_dirty_mb: 512
osc.lscratch*.checksum: 0
llite.lscratch*.max_cached_mb: 24576
llite.lscratch*.max_read_ahead_per_file_mb: 128
obdfilter.lscratch*.brw_size: 16
osd-ldiskfs.*.read_cache_enable: 0
osd-ldiskfs.*.writethrough_cache_enable: 0
debug: 0
jobid_name: %j:%u:%h
jobid_var: LUSTRE_JOBID
Fault Tolerance Mechanisms
Question asked
Does your system have a single point of failure as defined by “Definition 7” of a Production System? Please describe all mechanisms that provide fault tolerance for the submitted storage system. Be specific to your submission, not general storage system capabilities.
- Power (For example, can power failure of a node or rack bring down the storage system?)
- Networking (For example, can failure of a single NIC bring down the storage system? Remember that any networking failure that brings down multiple nodes is acceptable)
- Inter storage data and metadata server (For example, what type of data protection mechanism does the storage system use to keep operating during node failures, e.g., active-active servers, client-directed RAID, declustered RAID, erasure-coding, 3-way replication)
- Intra storage data and metadata server storage media (For example, how does the storage eysstem protect against fiailure of a single storage device within a node, e.g., raid5)
Please list any additional information needed to determine whether this system has a single point of failure.
The system does not have any single point of failure.
Several power sources are used to connect redundant power supply on the storage equipments.
HA server partners are connected to different switches in the Infiniband fabric in order to avoid unreachability of both partners in case of a switch failure.
All servers are used in an active-active fashion.
Controllers are associated by pairs. Their cache is mirrored and backed by a battery in a case of power failure.
Declustered RAID is using an 8+2 scheme in order to secure data even in the event of 1 or 2 drive failures in the same logical group. In case of drive failure, Declustered RAID allows for a fast rebuild to recover optimal data safety.
Execution
Question asked
Please provide a description of how the IO500 benchmark was executed, e.g., via system scheduler (e.g., SLURM) to run a job on the compute cluster, which initially ran a setup process to configure the client and file system, and then started the full benchmark.
During the IO500 benchmark execution was the system entirely dedicated to running the benchmark or were there other jobs running in the same cluster and storage system?
The io500 was performed using the Slurm batch scheduler.
During the execution, the system was not entirely dedicated to the benchmark, as there were a few other jobs running, but not using the same storage system, and also using other compute nodes.
So while the whole system was not dedicated, the resources used for the benchmark were.
Caching
Question asked
Please describe all caching mechanisms in client/server that were utilized during the IO500 run. This could include caching in any storage medium (e.g., SSD, RAM).
A few examples would include:
- Client data/metadata caching (in Linux page cache or in other memory cache)
- Client side NVMe read-only data cache
- Storage server metadata/data caching in RAM
- Storage controller caching
- RAID card caching
The caching mechanisms in play include:
- Client data/metadata in Linux page cache to a certain extent (limited by Lustre's max_dirty_mb parameter)
- Server-side writethrough and read page cache
- Storage controller caching (mirrored between controllers)
Data Source
Question asked
Is the submitted system a stand-alone storage system or an acceleration layer in front of another storage system that is the source of truth for all application data? This question relates to whether the submitted system is a burst buffer layered on primary storage or primary storage itself.
There is burst-buffer layer on this system.
The data source is the Declustered RAID based on NVMe storage.
Trust
Question asked
Please describe any steps taken to ensure that the results are trustworthy.
- Did you run the benchmark multiple times and get similar scores?
- Did you validate the score is below the physical capabilities of the deployed hardware?
- How did you validate that the storage system follows the IO500 rules regarding persistence, which states, "All data must be written to persistent storage within the measured time for the individual benchmark, e.g. if a file system caches data, it must ensure that data is persistently stored before acknowledging the close"?
Yes, the benchmark was run multiple times, yielding very close results each time.
The score is below the peak performance of the system.
Yes, the data used by the benchmark relies on persistent storage (NVMe drives in this case), and no burst-buffer layer in use.