Partitioning Data Volumes
Below is a simple question and answer format to understand the usage of data volume partitioning ,how it helps in improving over all HANA DB read and write performance and how this is different from data volume striping
1.What is data volume partitioning? How does it add performance advantage over default setup? Since when it is available?
Data volumes on the Indexserver can be partitioned so that read and write operations can run in parallel with increased data throughput. Also, the HANA startup time will benefit from this feature because the data throughput will increase massively, depending on the number and performance of the additional disks or volumes
The data files can now be segmented and stored in different locations and can then be accessed in parallel threads.
This feature is available since SAP HANA 2.0 SPS 03 .
2.How does SAP HANA data volume partitioning takes advantage of NFS filesystem type usage in HANA?
In the case of Network File Systems data can also be (along with parallel read) written in parallel across multiple connections. Partitioning data volumes in this way will therefore speed up all read/write operations on the volume including savepoints, merges, restart, table loading operations, and backups.
This feature enables the filesystem to have more parallel channels for processing I/O. To truly benefit from this feature additional mountpoints need to be configured for the additional locations of data volume partitions in order to leverage additional TCP connections in case of NFS. No further network configuration is required as long as the network infrastructure can sustain the additional workload
3.Can non-NFS type filesystems used in HANA takes benefit of data volume partitioning?
For non-NFS type filesystems the benefits of adopting the feature depends on setup provided by the hardware vendor / TDI design. Hence this has to be discussed with the vendor for feasibility as they responsible for designing the storage layout.
4.Can we use partitioning for log volumes in HANA?
NO,HANA data partitioning is only available for data volumes not for log volumes
5.When does data gets written to newly partitioned DATA volume in HANA ?
For a newly added data volume partition on an existing system, data is not immediately distributed . Fresh I/O writes are distributed to the new data volume partition and eventually the database achieves even distribution from a size point of view.
However,If immediate even distribution of data is required, we have to consider using SAP HANA backup and recovery (only file and backint based backup and recovery)