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Every SAP HANA node requires storage devices and capacity for:
In general, every directory that is created on the Isilon system has access to the total disk capacity of the Isilon cluster. If disk capacity for specific directories must be limited, you can apply SmartQuotas by using the Isilon quota-management tool. For more information, see SAP HANA installation.
The operating system is either SUSE Enterprise Linux for SAP Applications or Red Hat Enterprise Linux for SAP HANA. The operating system must be installed on local disks on the SAP HANA certified servers.
Every SAP HANA node requires access to a file system that is mounted under the local /hana/shared/ mount point for installation of the SAP HANA binary and configuration files, traces, and logs. An SAP HANA scale-out cluster requires a single shared file system, which must be mounted on every node. You can create the installation directory in the Isilon system.
To calculate the size of the /hana/shared/ file system, use the formulas in the SAP paper SAP HANA Storage Requirements. Version 2.10 of the paper provides the following formulas:
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
You can limit the disk size of the /hana/shared directory by using SmartQuotas. The following Isilon command limits the capacity of the /hana/shared directory /ifs/home/hana/shared to 400 GB:
isi quota quotas create /ifs/home/hana/shared directory --hard-threshold 400G --enforced true
For the SAP HANA data and log directories, Dell Technologies recommends enabling access to the overall Isilon cluster capacity for performance reasons instead of limiting the disk capacity by using SmartQuotas. If for any reason the disk capacity must be limited, use the following information for sizing the SmartQuotas.
The SAP HANA in-memory database requires disk storage for:
Every SAP HANA scale-up node and scale-out (worker) node requires two disk directories on the Isilon storage system. This is to save the in-memory database on disk (data) and keep a redo log (log). The size of these directories depends on the anticipated total memory requirement of the database and the RAM size of the node. To prepare the disk sizing, see the SAP paper SAP HANA Storage Requirements. Version 2.10 of the paper states that you can calculate the size of the data directory by using the following formula:
Sizedata = 1.2 x net disk space for data
The net disk space is the anticipated total memory requirement of the database plus 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, every node must have a 616 GB data volume assigned to it
(2 TB / 4 = 512 GB x 1.2 = 616 GB).
If the net disk space is unknown at the time of storage sizing, Dell Technologies recommends using the RAM size of the node plus 20 percent free space to calculate the capacity of the datafile system.
The size of the log directory depends on the RAM size of the node. The SAP HANA Storage Requirements paper provides the following formulas to calculate the minimum size of the log directory:
[systems ≤ 512GB ] Sizeredolog = 1/2 x RAM
[systems > 512GB ] Sizeredolog(min) = 512 GB