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Multiple hosts setup
This chapter describes the setup of a 2+1 SAP HANA multiple host system as example.
LUN configuration for SAP HANA multiple-hosts systems
At the SAP HANA host, volume groups and logical volumes need to be created and mounted, as indicated in the following table.
| Logical volume (LV) or volume | Mount point at SAP HANA host | Note |
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LV: FC5_data_mnt00001-vol |
/hana/data/FC5/mnt00001 |
Mounted using storage connector |
LV: FC5_log_mnt00001-vol |
/hana/log/FC5/mnt00001 |
Mounted using storage connector |
LV: FC5_data_mnt00002-vol |
/hana/data/FC5/mnt00002 |
Mounted using storage connector |
LV: FC5_log_mnt00002-vol |
/hana/log/FC5/mnt00002 |
Mounted using storage connector |
Volume: FC5_shared |
/hana/shared |
Mounted at all hosts using NFS and /etc/fstab entry |
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With the described configuration, the /usr/sap/FC5 directory in which the default home directory of user FC5adm is stored, is on the local disk for each HANA host. In a disaster recovery setup with disk-based replication, NetApp recommends creating four additional subdirectories in the FC5_shared volume for the /usr/sap/FC5 file system so that each database host has all its file systems on the central storage.
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Create LVM volume groups and logical volumes
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Initialize all LUNs as a physical volume.
pvcreate /dev/mapper/hana-FC5_data_mnt00001 pvcreate /dev/mapper/hana-FC5_data2_mnt00001 pvcreate /dev/mapper/hana-FC5_data_mnt00002 pvcreate /dev/mapper/hana-FC5_data2_mnt00002 pvcreate /dev/mapper/hana-FC5_log_mnt00001 pvcreate /dev/mapper/hana-FC5_log2_mnt00001 pvcreate /dev/mapper/hana-FC5_log_mnt00002 pvcreate /dev/mapper/hana-FC5_log2_mnt00002
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Create the volume groups for each data and log partition.
vgcreate FC5_data_mnt00001 /dev/mapper/hana-FC5_data_mnt00001 /dev/mapper/hana-FC5_data2_mnt00001 vgcreate FC5_data_mnt00002 /dev/mapper/hana-FC5_data_mnt00002 /dev/mapper/hana-FC5_data2_mnt00002 vgcreate FC5_log_mnt00001 /dev/mapper/hana-FC5_log_mnt00001 /dev/mapper/hana-FC5_log2_mnt00001 vgcreate FC5_log_mnt00002 /dev/mapper/hana-FC5_log_mnt00002 /dev/mapper/hana-FC5_log2_mnt00002
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Create a logical volume for each data and log partition. Use a stripe size that is equal to the number of LUNs used per volume group (in this example, it is two) and a stripe size of 256k for data and 64k for log. SAP only supports one logical volume per volume group.
lvcreate --extents 100%FREE -i 2 -I 256k --name vol FC5_data_mnt00001 lvcreate --extents 100%FREE -i 2 -I 256k --name vol FC5_data_mnt00002 lvcreate --extents 100%FREE -i 2 -I 64k --name vol FC5_log_mnt00002 lvcreate --extents 100%FREE -i 2 -I 64k --name vol FC5_log_mnt00001
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Scan the physical volumes, volume groups, and vol groups at all other hosts.
modprobe dm_mod pvscan vgscan lvscan
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If these commands do not find the volumes, a restart is required. |
To mount the logical volumes, the logical volumes must be activated. To activate the volumes, run the following command:
vgchange -a y
Create file systems
Create the XFS file system on all data and log logical volumes.
mkfs.xfs FC5_data_mnt00001-vol mkfs.xfs FC5_data_mnt00002-vol mkfs.xfs FC5_log_mnt00001-vol mkfs.xfs FC5_log_mnt00002-vol
Create mount points
Create the required mount point directories, and set the permissions on all worker and standby hosts:
sapcc-hana-tst:/ # mkdir -p /hana/data/FC5/mnt00001 sapcc-hana-tst:/ # mkdir -p /hana/log/FC5/mnt00001 sapcc-hana-tst:/ # mkdir -p /hana/data/FC5/mnt00002 sapcc-hana-tst:/ # mkdir -p /hana/log/FC5/mnt00002 sapcc-hana-tst:/ # mkdir -p /hana/shared sapcc-hana-tst:/ # chmod –R 777 /hana/log/FC5 sapcc-hana-tst:/ # chmod –R 777 /hana/data/FC5 sapcc-hana-tst:/ # chmod 777 /hana/shared
Mount file systems
To mount the /hana/shared file systems during system boot using the /etc/fstab configuration file, add the /hana/shared file system to the /etc/fstab configuration file of each host.
sapcc-hana-tst:/ # cat /etc/fstab <storage-ip>:/hana_shared /hana/shared nfs rw,vers=3,hard,timeo=600, intr,noatime,nolock 0 0
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All the data and log file systems are mounted through the SAP HANA storage connector. |
To mount the file systems, run the mount –a command at each host.