E20-526 Sample Questions Answers

Oracle Database performs I/O on data files in multiples of the database block size (db_block_size), which is 8KB by default. The default Oracle Database block size is optimal on XtremIO. XtremIO supports larger block sizes as well. In the case of multiblock I/O (e.g., table/index scans with access method full), one should tune the Oracle Database initialization parameter db_file_multiblock_read_count to limit the requests to 128KB.

Therefore, the formula for db_file_multiblock_read_count is:

db_file_multiblock_read_count = 128KB / db_block_size

In our case the block size is 1 MB, so the formula db_file_multiblock_read_count is 1 MB/ 8KB = 1024/8 = 128

References:https://www.emc.com/collateral/white-papers/h13497-oracle-best-practices-xtremio-wp.pdf , page 21

Noting the inefficiencies in VMware’s NMP driver, EMC developed a set of drivers specifically designed to overcome these limitations and improve the performance and reliability of the data passing between an array and a server. EMC developed the PowerPath family of products optimized specifically for Linux, Microsoft Windows, and UNIX Operating Systems as well as PowerPath/VE for VMware vSphere and Microsoft Hyper-V hypervisors.

PowerPath is installed on hosts to provide path failover, load balancing and performance optimization VPLEX engines (or directly to the XtremIO array if VPLEX is not used).

Note: VMware, with the cooperation of its storage partners, developed a Native Multipathing Plug-in (NMP). VMware NMP was designed to distribute the load over all the available paths and provide failover protection in the case of path, port or HBA failure, but it has not been fully optimized to work with the controllers in a storage systems. VMware’s NMP Round Robin policy does not have the intelligence that PowerPath has as PowerPath uses testing and diagnostics to continually monitor an environment to determine the optimal path for queuing requests and will adapt to current conditions.

References:https://www.emc.com/collateral/analyst-reports/emc-taneja-group-powerpath-tb.pdf

When a copy is created, the volume's existing metadata becomes an "ancestor" entity (parent object) that is shared between the production volume and the copy. New empty containers are created for subsequent changes to both the production volume and the virtual copy volume. Therefore, the act of creating a copy is instantaneous and involves no data or metadata copies.

References: https://www.emc.com/collateral/white-paper/h13035-wp-introduction-to-xtremio-snapshots.pdf, pages 18

Each Storage Controller includes two 8Gb/s Fibre Channel (FC) ports.

References: Introduction to the EMC XtremIO STORAGE ARRAY (April 2015), page 8

Best practice is to use four LUNs for the DATA disk group to allow the host to use simultaneous threads. The REDO and FRA disk groups should use two LUNs each.

References:https://community.emc.com/community/connect/everything_oracle/blog/2016/03/31/best-practises-of-vblock-on-xtremio-with-oracle-databases-part-i

The default setting for XtremIO volumes is 512e. It is recommended not to alter this in order to use 4K Advanced Format for Oracle Database deployments. There are no performance ramifications when using 512e volumes in conjunction with an Oracle database. On the contrary, 4K Advanced Format is rejected by many elements of the Oracle and Linux operating system stack.

References:https://www.emc.com/collateral/white-papers/h13497-oracle-best-practices-xtremio-wp.pdf , page 20