EXAScaler Cloud by DDN: A shared file system to use with SAS Grid on Google Cloud Platform (GCP)

MargaretC — Fri, 21 May 2021 19:15:48 GMT

SAS recently tested SAS 9.4 on GCP instances using EXAScaler Cloud by DDN: Google Marketplace - EXAScaler Cloud. The results of the testing were very favorable.

The test infrastructure consisted of 21 GCP instances defined like this:

Three n2-standard-32 instances for the SAS clients – each with 9 TB of local SSD storage.
Sixteen n1-standard-16 instances for the OSS hosts – each with 4.3 TB of pd-balanced (balanced persistent disks) storage
One n1-standard-4 instance for the MGS host – with 2 TB of pd-ssd (SSD persistent disks) storage
One n1-standard-32 instance for the MDS host – with 1 TB of pd-balanced storage.
EXAScaler 5.1.1 was used for the testing.

For the test, the following EXAScaler tunings were applied:

OSS tuning - Run on all OSS nodes

lctl set_param osd-ldiskfs.*.read_cache_enable=0 osd-ldiskfs.*.writethrough_cache_enable=0 obdfilter.*.brw_size=16 obdfilter.*.precreate_batch=1024

Lustre client tuning - Run on all client nodes

lctl set_param mdc.*.max_rpcs_in_flight=128 osc.*.max_pages_per_rpc=16M osc.*.max_rpcs_in_flight=16 osc.*.max_dirty_mb=1024 llite.*.max_read_ahead_mb=2048 osc.*.checksums=0 llite.*.max_read_ahead_per_file_mb=256

And the following file system tuning was applied:

lfs setstripe -c -1 -S 4M < file system subdirectory >

rhel_iotest results:

The 1-node test gave us 221 MB per second per physical core for WRITEs and 333 MB per second per physical core for READs.

The 2-node test gave us 226 MB per second per physical core for WRITEs and 337 MB per second per physical core for READs.

The 3-node test gave us 230 MB per second per physical core for WRITEs and 325 MB per second per physical core for READs.

Please note that SAS recommends a minimum of 100 MB per second per physical core for WRITEs and READs.

As you can see, the above EXAScaler Cloud infrastructure can produce the minimum IO throughput needs of a 64-core SAS Grid application. Please reach out to DDN for more details on EXAScaler Cloud and how to configure it for optimal performance in GCP.

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EXAScaler Cloud by DDN: A shared file system to use with SAS Grid on Google Cloud Platform (GCP)