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Every SAP HANA node requires storage devices and capacity for the following:
Note: The formulas for capacity sizing in SAP HANA Storage Requirements are subject to change by SAP. Always check the latest version of the white paper for updates before you determine capacity requirements.
The overall capacity calculation for the SAP HANA installation must include the required capacity for the operating system when the SAP HANA nodes boot from a volume on an SC Series model, that is, when they boot from the SAN.
Every SAP HANA node requires approximately 100 GB capacity for the operating system, including space for the /usr/sap/ directory. When booting from a SAN, follow the best practices in the Dell Compellent Storage Center and Boot from SAN with FCoE Best Practices Guide.
SAP HANA installation (/hana/shared)
For installation of the SAP HANA binaries, as well as the configuration files, traces, and logs, every SAP HANA node requires access to a file system that is mounted under the local mount point, /hana/shared. An SAP HANA scale-out cluster requires a single shared file system, which must be mounted on every node. Most SAP HANA installations use an NFS file system for the single shared file system. The file system you choose depends on your infrastructure and requirements. The options are:
The SC Series array uses block storage, which can be used to create a shared file system using a cluster file system such as General Parallel File System (GPFS) or Oracle Cluster File System 2 (OCFS2) on top of the block LUNs. SUSE provides OCFS2 capabilities with the HA package (a SUSE license is required). The HA package is also part of the SUSE Linux Enterprise Server (SLES) for SAP applications distribution that is used by most of the SAP HANA appliance vendors.
Single node (scale-up):
Sizeinstallation(single-node) = MIN(1 x RAM; 1 TB)
Multinode (scale-out):
Sizeinstallation(scale-out) = 1 x RAM_of_worker per 4 worker nodes
The SAP HANA in-memory database requires disk storage to:
Every SAP HANA node (scale-up) or worker node (scale-out) requires two disk volumes to save the in-memory database on disk (data) and to keep a redo log (log). The size of these volumes depends on the anticipated total memory requirement of the database and the RAM size of the node. To help you prepare the disk sizing, SAP provides references to tools and documents in SAP HANA Storage Requirements. Version 2.10 (February 2017) of the document provides the following formulas to calculate the size of the data volume.
Sizedata = 1.2x anticipated net disk space for data
In this formula, net disk space for data is the anticipated total memory requirement of the database plus an additional 20 percent free space. If the database is distributed across multiple nodes in a scale-out cluster, divide the net disk space by the number of SAP HANA worker nodes in the cluster. For example, if the net disk space is 2 TB and the scale-out cluster consists of four worker nodes, then every node must be assigned a 616 GB data volume (2 TB / 4 = 512 GB x 1.2 = 616 GB).
If the net disk space is unknown at the time of the storage sizing, we recommend using the RAM size of the node plus 20 percent free space for a capacity calculation of the data file system.
Sizedata = 1 x RAM
The size of the log volume depends on the RAM size of the node. SAP HANA Storage Requirements provides the following formulas to calculate the minimum size of the log volume:
[systems ≤ 512GB ] Sizeredolog = 1/2 x RAM
[systems > 512GB ] Sizeredolog(min) = 512 GB
SAP HANA supports backup to a file system or to SAP-certified third-party tools. Dell EMC supports data protection strategies for SAP HANA backup using Dell EMC Data Domain systems and Dell EMC NetWorker software. Although it is possible to back up an SAP HANA database to a file system on a SC Series all-flash or hybrid array, we do not recommend backing up the SAP HANA database to the storage array where the primary persistence resides. If you plan to back up SAP HANA to a NFS file system on a different storage array, see SAP HANA Storage Requirements for details about sizing the backup file system. The capacity depends on not only the data size and the frequency of change operations in the database but also the backup generations kept on disk.
Configure switch zoning so that each host can detect all virtual ports on all storage arrays. For detailed zoning best practices, see the documentation for your fabric switch and storage array.
To avoid any impact to SAP HANA operation, configure the HBA driver settings to process controller failover in dual-controller configurations. To do this, add the following required entry to the /etc/modprobe.conf.local file:
options qla2xxx qlport_down_retry=5
For information about setting up SC Series storage arrays, see the Dell EMC support documentation for your array.