Block size
Choose the file system block size based on the projected workload of the file system and the type of storage that it uses.
I/O Type | Examples of applications | Block size |
---|---|---|
Large sequential I/O | Scientific computing, Digital media, File-based analytics | 1 -16 MiB |
Relational database | DB2®, Oracle, Small files on ESS | 512 KiB |
Small sequential I/O | General File Service, Email, Web applications | 256 KiB |
Workload | Configuration type | Block size |
---|---|---|
SAP HANA | ESS GL | 1 MiB for metadata 16 MiB for data |
SAP HANA | FPO | 1 MiB for single pool 256 KiB for metadata only 2 MiB for data only |
Hadoop | ESS GL | 1 MiB for metadata only 8 MiB for data only |
Hadoop | FPO | 256 KiB for metadata only 2 MiB for data only |
Spark | FPO | 256 KiB for metadata only 2 MiB for data only |
SAP Sybase IQ | ESS GL | 256 KiB - 1 MiB for metadata only 16 MiB for data only |
Healthcare (Medical Imaging) | ESS GL | 256 KiB for metadata only 1 MiB for data only |
Healthcare (Medical Imaging) | Other Storage - IBM Spectrum Scale deployed with Block Storage at the backend. See the tip below. | 256 KiB for metadata and data |
Archive | Other Storage - IBM Spectrum Scale deployed with Block Storage at the backend. See the tip below. | Depends on the filesize. |
ECM | Other Storage - IBM Spectrum Scale deployed with Block Storage at the backend. See the tip below. | 256 KiB Unless the content is very large files (For example - Videos). |
Oracle | Other Storage - IBM Spectrum Scale deployed with Block Storage at the backend. See the tip below. | 256 KiB for metadata and data |
Technical Computing | ESS GL | 1 MiB metadata 4 - 16 MiB data depending on importance of peak sequential performance. |
SAS | ESS GL | 1 MiB metadata 8 - 16 MiB depending on the SASBUF size (128 KiB or 256 KiB) |
Enterprise File (Misc Projects, data sharing) | Other Storage - IBM Spectrum Scale deployed with Block Storage at the backend. See the tip below. | 256 KiB metadata and data |
For more information about IBM Spectrum Scale RAID, see IBM Spectrum Scale RAID: Administration in the Elastic Storage Server documentation on IBM® Knowledge Center.
The --metadata-block-size option on the mmcrfs command allows a different block size to be specified for the system storage pool, provided its usage is set to metadataOnly. This can be beneficial if the file system block size is larger than 1 MB. Valid values are the same as those listed for the -B option.
- More blocks are required to store a given amount of data resulting in additional work to allocate those blocks
- One block of allocation map data contains less information