Certified Configuration Settings

The Storage Array

This is the storage connected to the DataCore Server that will be used for SANsymphony disk pools managing SAP HANA virtual disk (vDisk) storage sources. The storage must use Fibre Channel (FC) connectivity and meet SAP HANA certified storage requirements. Refer to the SAP HANA Hardware Directory for details.

The DataCore Server

Server Hardware

The DataCore Server must be a physical machine. SANsymphony instances running in virtual machines (VM) are not supported for SAP HANA deployments. For a complete list of SAP-certified vendors providing server hardware that can be used for DataCore Servers, visit the official SAP website.

Operating System

Only Windows ‘Standard’ or ‘Datacenter’ editions are supported. Other Windows editions (‘Essential’ or ‘Storage Server’) are not supported for SAP HANA. For more information, refer to the Prerequisites section.

DataCore recommends the use of ‘vanilla’ Windows operating system deployments although a server hardware vendor’s own ‘OEM’ installation is allowed only if it is either a ‘Standard’ or ‘Datacenter’ edition.

SANsymphony Software

DataCore SANsymphony 10.0 PSP12 or later.

Server Ports (FC SCSI Only)

FC SCSI only. iSCSI and NVMe/oF ports are not certified. Any front-end (FE) and mirror (MR) ports used by SAP HANA hosts for their vDisks must not be used by any other hosts that are not running SAP HANA. This also includes not using any back-end (BE) ports used to connect to storage of SANsymphony disk pools that are used for the SAP HANA host’s storage sources.

Disk Pools

Disk pools used for any type of storage source used by SAP HANA hosts must not be used by any other host. This includes storage sources for vDisks, logstores, mapstores or history logs. Disk pool encryption is supported although the performance of encrypted vDisks will be slightly lower than unencrypted it will still be in the range of SAP HANA’s performance requirements. The disk pool ‘Capacity Optimization’ feature is not supported.

Virtual Disks

Dedicated DataCore Servers are not a requirement if SAP HANA vDisks have their designated disk pool(s) for all their vDisk’s storage sources and their dedicated server ports for all mappings (see Server Ports (FC SCSI Only) section). vDisk encryption is supported (see Disk Pools section).

The SAP HANA Host

Operating System and HANA Version

SUSE Linux and HANA versions must match those listed in SAP note 2235581 - SAP HANA: Supported Operating Systems.

Server Ports (FC SCSI Only)

FC SCSI only. ISCSI and NVMe/oF ports are not certified.

SCSI Disk Timeout

This should be set to 80 seconds for all SCSI devices created from SANsymphony virtual disks. The timeout for a given SCSI device can be checked using the ‘cat’ command.

Example:

cat /sys/block/sda/device/timeout

There are two methods that can be used to change the SCSI disk timeout for a given device.

  • Use the ‘echo’ command – this is temporary and will not survive the next reboot of the Linux host server.
  • Create a custom ‘udev rule’ – this is permanent but will require a reboot for the setting to take effect.

Using the ‘echo’ Command (will not survive a reboot)

Set the SCSI Disk timeout value to 80 seconds:

echo 80 > /sys/block/[disk_device]/device/timeout

Creating a custom ‘udev’ Rule (permanent but requires a reboot)

Create a file called ‘/etc/udev/rules.d/99-datacore.rules’ with the following settings:

SUBSYSTEM=="block", ACTION=="add", ATTRS{vendor}=="DataCore", ATTRS{model}=="Virtual Disk ", RUN+="/bin/sh -c 'echo 80 > /sys/block/%k/device/timeout'"

Refer to the KB article for more information.

This KB article applies to all current versions of SANsymphony 10.x as well.

  • Make sure that the udev rule is exactly as written above. Else this may result in the Linux operating system defaulting back to 30 seconds.
  • There are four blank whitespace characters after the ATTRS{model} string which much be observed otherwise paths to SANsymphony virtual disks may not be re-discovered.

ALUA Settings

Hosts must be configured for ALUA. hosts without ALUA configured are not certified. See Registering hosts for more information.

Multipath Configuration

The 'defaults' section

Add or modify the polling_interval to a value of 60 (seconds).

defaults { polling_interval 60 }

This tells the host how often to check for access on a previously failed virtual disk path. A smaller setting will interfere with host performance. Do not add this parameter to the 'device' section of the multipath configuration file (see below) as it will prevent the polling from working as expected.

The 'device' section

All the following entries listed are DataCore-required values. See the notes section for more specific technical details.

device {
vendor "DataCore"
product "Virtual Disk"
path_checker tur
prio alua
hardware_handler "1 alua"
failback 10
rr_weight priorities
no_path_retry fail
dev_loss_tmo 60
fast_io_fail_tmo 5
rr_min_io_rq 100
path_grouping_policy group_by_prio
}
  • No other settings and/or values should be used.
  • device section must be encapsulated by a devices section.
  • vendor / product: This is the Vital Product Information presented from SANsymphony for all virtual disks. Refer to the SCSI Standard Inquiry section from the online help.
  • hardware_handler: This value is required to make sure ALUA always behaves as expected.
  • failback (seconds): Adds an additional ‘wait’ period after SANsymphony has switched the ‘Host Access’ virtual disk state to 'Allowed’ to prevent flip-flopping failback attempts.